diff --git a/src/qutip_qip/algorithms/__init__.py b/src/qutip_qip/algorithms/__init__.py
index 8bdea8f7..010b80ed 100644
--- a/src/qutip_qip/algorithms/__init__.py
+++ b/src/qutip_qip/algorithms/__init__.py
@@ -1,2 +1,5 @@
 from .qft import *
 from .qpe import *
+from .error_correction.bit_flip import *
+from .error_correction.phase_flip import *
+from .error_correction.shor_code import *
diff --git a/src/qutip_qip/algorithms/error_correction/bit_flip.py b/src/qutip_qip/algorithms/error_correction/bit_flip.py
new file mode 100644
index 00000000..b4d3a0b8
--- /dev/null
+++ b/src/qutip_qip/algorithms/error_correction/bit_flip.py
@@ -0,0 +1,112 @@
+# bit_flip_code.py
+
+import numpy as np
+from qutip import Qobj, tensor, basis, sigmax, sigmay
+from qutip_qip.operations import Gate
+from qutip_qip.circuit import QubitCircuit
+
+__all__ = ["BitFlipCode"]
+
+
+class BitFlipCode:
+    """
+    Implementation of the 3-qubit bit-flip code.
+
+    The bit-flip code protects against X (bit-flip) errors by encoding
+    a single logical qubit across three physical qubits:
+    |0⟩ → |000⟩
+    |1⟩ → |111⟩
+    """
+
+    @staticmethod
+    def encode_circuit():
+        """
+        Create a circuit for encoding a single qubit into the 3-qubit bit-flip code.
+
+        Returns
+        -------
+        qc : instance of QubitCircuit
+            Encoding circuit for the bit-flip code.
+        """
+        qc = QubitCircuit(3)
+        qc.add_gate("CNOT", controls=0, targets=1)
+        qc.add_gate("CNOT", controls=0, targets=2)
+        return qc
+
+    @staticmethod
+    def syndrome_measurement_circuit():
+        """
+        Create a circuit for syndrome measurement of the 3-qubit bit-flip code.
+
+        Returns
+        -------
+        qc : instance of QubitCircuit
+            Syndrome measurement circuit that uses two ancilla qubits.
+        """
+        qc = QubitCircuit(5)  # 3 data qubits + 2 syndrome qubits
+
+        # First syndrome measurement: Parity of qubits 0 and 1
+        qc.add_gate("CNOT", controls=0, targets=3)
+        qc.add_gate("CNOT", controls=1, targets=3)
+
+        # Second syndrome measurement: Parity of qubits 1 and 2
+        qc.add_gate("CNOT", controls=1, targets=4)
+        qc.add_gate("CNOT", controls=2, targets=4)
+
+        return qc
+
+    @staticmethod
+    def correction_circuit(syndrome):
+        """
+        Create a circuit for error correction based on syndrome measurement.
+
+        Parameters
+        ----------
+        syndrome : tuple
+            Two-bit syndrome measurement result (s1, s2).
+
+        Returns
+        -------
+        qc : instance of QubitCircuit
+            Correction circuit applying X gates as needed.
+        """
+        qc = QubitCircuit(3)
+        s1, s2 = syndrome
+
+        # Syndrome interpretation:
+        # s1=0, s2=0: No error
+        # s1=1, s2=0: Error on qubit 0
+        # s1=1, s2=1: Error on qubit 1
+        # s1=0, s2=1: Error on qubit 2
+
+        if s1 == 1 and s2 == 0:
+            # Error on qubit 0
+            qc.add_gate("X", targets=0)
+        elif s1 == 1 and s2 == 1:
+            # Error on qubit 1
+            qc.add_gate("X", targets=1)
+        elif s1 == 0 and s2 == 1:
+            # Error on qubit 2
+            qc.add_gate("X", targets=2)
+
+        return qc
+
+    @staticmethod
+    def decode_circuit():
+        """
+        Create a circuit for decoding the 3-qubit bit-flip code.
+
+        Returns
+        -------
+        qc : instance of QubitCircuit
+            Decoding circuit for the bit-flip code.
+        """
+        qc = QubitCircuit(3)
+        qc.add_gate("CNOT", controls=0, targets=2)
+        qc.add_gate("CNOT", controls=0, targets=1)
+
+        # Add a Toffoli gate to verify the parity
+        # If all qubits have the same value, the result is stored in qubit 0
+        qc.add_gate("TOFFOLI", controls=[1, 2], targets=0)
+
+        return qc
diff --git a/src/qutip_qip/algorithms/error_correction/phase_flip.py b/src/qutip_qip/algorithms/error_correction/phase_flip.py
new file mode 100644
index 00000000..c591bfc7
--- /dev/null
+++ b/src/qutip_qip/algorithms/error_correction/phase_flip.py
@@ -0,0 +1,131 @@
+import numpy as np
+from qutip import Qobj, tensor, basis, sigmax, sigmay, sigmaz
+from qutip_qip.operations import Gate
+from qutip_qip.circuit import QubitCircuit
+
+__all__ = ["PhaseFlipCode"]
+
+
+class PhaseFlipCode:
+    """
+    Implementation of the 3-qubit phase-flip code.
+    The phase-flip code protects against Z (phase-flip) errors by encoding
+    a single logical qubit across three physical qubits:
+    |0⟩ → |+++⟩
+    |1⟩ → |---⟩
+
+    This is accomplished by applying Hadamard gates to transform the bit-flip code
+    into the phase-flip code, as phase errors in the Hadamard basis appear as bit-flips.
+    """
+
+    @staticmethod
+    def encode_circuit():
+        """
+        Create a circuit for encoding a single qubit into the 3-qubit phase-flip code.
+
+        Returns
+        -------
+        qc : instance of QubitCircuit
+            Encoding circuit for the phase-flip code.
+        """
+        qc = QubitCircuit(3)
+
+        # First apply Hadamard to the input qubit
+        qc.add_gate("SNOT", targets=0)
+
+        # Then use the bit-flip encoding structure
+        qc.add_gate("CNOT", controls=0, targets=1)
+        qc.add_gate("CNOT", controls=0, targets=2)
+
+        # Apply Hadamard gates to all qubits
+        qc.add_gate("SNOT", targets=0)
+        qc.add_gate("SNOT", targets=1)
+        qc.add_gate("SNOT", targets=2)
+
+        return qc
+
+    @staticmethod
+    def syndrome_measurement_circuit():
+        """
+        Create a circuit for syndrome measurement of the 3-qubit phase-flip code.
+
+        Returns
+        -------
+        qc : instance of QubitCircuit
+            Syndrome measurement circuit that uses two ancilla qubits.
+        """
+        qc = QubitCircuit(5)  # 3 data qubits + 2 syndrome qubits
+
+        qc.add_gate("SNOT", targets=0)
+        qc.add_gate("SNOT", targets=1)
+        qc.add_gate("SNOT", targets=2)
+
+        qc.add_gate("CNOT", controls=0, targets=3)
+        qc.add_gate("CNOT", controls=1, targets=3)
+
+        qc.add_gate("CNOT", controls=1, targets=4)
+        qc.add_gate("CNOT", controls=2, targets=4)
+
+        qc.add_gate("SNOT", targets=0)
+        qc.add_gate("SNOT", targets=1)
+        qc.add_gate("SNOT", targets=2)
+
+        return qc
+
+    @staticmethod
+    def correction_circuit(syndrome):
+        """
+        Create a circuit for error correction based on syndrome measurement.
+
+        Parameters
+        ----------
+        syndrome : tuple
+            Two-bit syndrome measurement result (s1, s2).
+
+        Returns
+        -------
+        qc : instance of QubitCircuit
+            Correction circuit applying Z gates as needed.
+        """
+        qc = QubitCircuit(3)
+        s1, s2 = syndrome
+
+        # Syndrome interpretation:
+        # s1=0, s2=0: No error
+        # s1=1, s2=0: Error on qubit 0
+        # s1=1, s2=1: Error on qubit 1
+        # s1=0, s2=1: Error on qubit 2
+
+        if s1 == 1 and s2 == 0:
+            qc.add_gate("Z", targets=0)
+        elif s1 == 1 and s2 == 1:
+            qc.add_gate("Z", targets=1)
+        elif s1 == 0 and s2 == 1:
+            qc.add_gate("Z", targets=2)
+
+        return qc
+
+    @staticmethod
+    def decode_circuit():
+        """
+        Create a circuit for decoding the 3-qubit phase-flip code.
+
+        Returns
+        -------
+        qc : instance of QubitCircuit
+            Decoding circuit for the phase-flip code.
+        """
+        qc = QubitCircuit(3)
+
+        qc.add_gate("SNOT", targets=0)
+        qc.add_gate("SNOT", targets=1)
+        qc.add_gate("SNOT", targets=2)
+
+        qc.add_gate("CNOT", controls=0, targets=2)
+        qc.add_gate("CNOT", controls=0, targets=1)
+
+        qc.add_gate("TOFFOLI", controls=[1, 2], targets=0)
+
+        qc.add_gate("SNOT", targets=0)
+
+        return qc
diff --git a/src/qutip_qip/algorithms/error_correction/shor_code.py b/src/qutip_qip/algorithms/error_correction/shor_code.py
new file mode 100644
index 00000000..735a9864
--- /dev/null
+++ b/src/qutip_qip/algorithms/error_correction/shor_code.py
@@ -0,0 +1,66 @@
+import numpy as np
+from qutip import Qobj, tensor, basis, sigmax, sigmay, sigmaz
+from qutip_qip.operations import Gate
+from qutip_qip.circuit import QubitCircuit
+
+__all__ = ["ShorCode"]
+
+
+class ShorCode:
+    """
+    Implementation of the 9-qubit Shor code.
+
+    The Shor code protects against arbitrary single-qubit errors by combining
+    the 3-qubit phase-flip code with the 3-qubit bit-flip code.
+
+    The logical states are encoded as:
+    |0⟩ → (|000⟩ + |111⟩)(|000⟩ + |111⟩)(|000⟩ + |111⟩) / 2√2
+    |1⟩ → (|000⟩ - |111⟩)(|000⟩ - |111⟩)(|000⟩ - |111⟩) / 2√2
+
+    This encoding allows correction of any single-qubit error (bit-flip, phase-flip,
+    or both) on any of the 9 physical qubits.
+    """
+
+    @staticmethod
+    def encode_circuit():
+        """
+        Create a circuit for encoding a single qubit into the 9-qubit Shor code.
+
+        The encoding process:
+        1. Apply phase-flip encoding to the input (creating |+++⟩ or |---⟩)
+        2. Apply bit-flip encoding to each of the three qubits
+
+        Returns
+        -------
+        qc : instance of QubitCircuit
+            Encoding circuit for the Shor code.
+        """
+        qc = QubitCircuit(9)
+
+        # Step 1: Phase-flip encoding on the first qubit
+        # Apply Hadamard to the input qubit
+        qc.add_gate("SNOT", targets=0)
+
+        # Create the GHZ-like state by using CNOTs
+        qc.add_gate("CNOT", controls=0, targets=3)
+        qc.add_gate("CNOT", controls=0, targets=6)
+
+        # Apply Hadamard to all three qubits
+        qc.add_gate("SNOT", targets=0)
+        qc.add_gate("SNOT", targets=3)
+        qc.add_gate("SNOT", targets=6)
+
+        # Step 2: Bit-flip encoding for each of the three blocks
+        # First block: qubits 0,1,2
+        qc.add_gate("CNOT", controls=0, targets=1)
+        qc.add_gate("CNOT", controls=0, targets=2)
+
+        # Second block: qubits 3,4,5
+        qc.add_gate("CNOT", controls=3, targets=4)
+        qc.add_gate("CNOT", controls=3, targets=5)
+
+        # Third block: qubits 6,7,8
+        qc.add_gate("CNOT", controls=6, targets=7)
+        qc.add_gate("CNOT", controls=6, targets=8)
+
+        return qc
diff --git a/tests/test_bit_flip.py b/tests/test_bit_flip.py
new file mode 100644
index 00000000..cd7e23ac
--- /dev/null
+++ b/tests/test_bit_flip.py
@@ -0,0 +1,89 @@
+import pytest
+import numpy as np
+from qutip_qip.algorithms import BitFlipCode
+
+
+def test_encode_circuit_structure():
+    """Test that the encoding circuit has the correct structure."""
+    qc = BitFlipCode.encode_circuit()
+
+    # Check circuit has correct number of qubits
+    assert qc.N == 3
+
+    # Check it has 2 CNOT gates
+    assert len(qc.gates) == 2
+    assert all(gate.name == "CNOT" for gate in qc.gates)
+
+    # Check gate connections - QubitCircuit uses lists for controls and targets
+    assert qc.gates[0].controls == [0]
+    assert qc.gates[0].targets[0] == 1
+    assert qc.gates[1].controls == [0]
+    assert qc.gates[1].targets[0] == 2
+
+
+def test_syndrome_measurement_circuit_structure():
+    """Test that the syndrome measurement circuit has the correct structure."""
+    qc = BitFlipCode.syndrome_measurement_circuit()
+
+    # Check circuit has correct number of qubits (3 data + 2 syndrome)
+    assert qc.N == 5
+
+    # Check it has 4 CNOT gates
+    assert len(qc.gates) == 4
+    assert all(gate.name == "CNOT" for gate in qc.gates)
+
+    # Check gate connections for syndrome measurement
+    assert qc.gates[0].controls == [0] and qc.gates[0].targets[0] == 3
+    assert qc.gates[1].controls == [1] and qc.gates[1].targets[0] == 3
+    assert qc.gates[2].controls == [1] and qc.gates[2].targets[0] == 4
+    assert qc.gates[3].controls == [2] and qc.gates[3].targets[0] == 4
+
+
+def test_correction_circuit_no_error():
+    """Test correction circuit with no error (syndrome 00)."""
+    qc = BitFlipCode.correction_circuit((0, 0))
+    assert qc.N == 3
+    assert len(qc.gates) == 0  # No correction needed
+
+
+def test_correction_circuit_qubit0_error():
+    """Test correction circuit with error on qubit 0 (syndrome 10)."""
+    qc = BitFlipCode.correction_circuit((1, 0))
+    assert qc.N == 3
+    assert len(qc.gates) == 1
+    assert qc.gates[0].name == "X" and qc.gates[0].targets[0] == 0
+
+
+def test_correction_circuit_qubit1_error():
+    """Test correction circuit with error on qubit 1 (syndrome 11)."""
+    qc = BitFlipCode.correction_circuit((1, 1))
+    assert qc.N == 3
+    assert len(qc.gates) == 1
+    assert qc.gates[0].name == "X" and qc.gates[0].targets[0] == 1
+
+
+def test_correction_circuit_qubit2_error():
+    """Test correction circuit with error on qubit 2 (syndrome 01)."""
+    qc = BitFlipCode.correction_circuit((0, 1))
+    assert qc.N == 3
+    assert len(qc.gates) == 1
+    assert qc.gates[0].name == "X" and qc.gates[0].targets[0] == 2
+
+
+def test_decode_circuit_structure():
+    """Test that the decoding circuit has the correct structure."""
+    qc = BitFlipCode.decode_circuit()
+
+    # Check circuit has correct number of qubits
+    assert qc.N == 3
+
+    # Check it has 2 CNOT gates and 1 TOFFOLI gate
+    assert len(qc.gates) == 3
+    assert qc.gates[0].name == "CNOT"
+    assert qc.gates[1].name == "CNOT"
+    assert qc.gates[2].name == "TOFFOLI"
+
+    # Check gate connections
+    assert qc.gates[0].controls == [0] and qc.gates[0].targets[0] == 2
+    assert qc.gates[1].controls == [0] and qc.gates[1].targets[0] == 1
+    assert qc.gates[2].controls == [1, 2] and qc.gates[2].targets[0] == 0
diff --git a/tests/test_phase_flip.py b/tests/test_phase_flip.py
new file mode 100644
index 00000000..f3005186
--- /dev/null
+++ b/tests/test_phase_flip.py
@@ -0,0 +1,134 @@
+import pytest
+import numpy as np
+from qutip import Qobj, tensor, basis, fidelity
+from qutip_qip.algorithms import PhaseFlipCode
+
+
+def test_encode_circuit_structure():
+    """Test that the encoding circuit has the correct structure."""
+    qc = PhaseFlipCode.encode_circuit()
+
+    # Check circuit has correct number of qubits
+    assert qc.N == 3
+
+    # Check it has correct number of gates (1 H + 2 CNOT + 3 H = 6 gates)
+    assert len(qc.gates) == 6
+
+    # Check first gate is Hadamard on qubit 0
+    assert qc.gates[0].name == "SNOT"
+    assert qc.gates[0].targets[0] == 0
+
+    # Check CNOT gates
+    assert qc.gates[1].name == "CNOT"
+    assert qc.gates[1].controls == [0]
+    assert qc.gates[1].targets[0] == 1
+
+    assert qc.gates[2].name == "CNOT"
+    assert qc.gates[2].controls == [0]
+    assert qc.gates[2].targets[0] == 2
+
+    # Check final Hadamard gates on all qubits
+    assert qc.gates[3].name == "SNOT"
+    assert qc.gates[3].targets[0] == 0
+
+    assert qc.gates[4].name == "SNOT"
+    assert qc.gates[4].targets[0] == 1
+
+    assert qc.gates[5].name == "SNOT"
+    assert qc.gates[5].targets[0] == 2
+
+
+def test_syndrome_measurement_circuit_structure():
+    """Test that the syndrome measurement circuit has the correct structure."""
+    qc = PhaseFlipCode.syndrome_measurement_circuit()
+
+    # Check circuit has correct number of qubits (3 data + 2 syndrome)
+    assert qc.N == 5
+
+    # Check it has the correct number of gates (3 H + 4 CNOT + 3 H = 10 gates)
+    assert len(qc.gates) == 10
+
+    # Check first three Hadamard gates on data qubits
+    for i in range(3):
+        assert qc.gates[i].name == "SNOT"
+        assert qc.gates[i].targets[0] == i
+
+    # Check CNOT gates for syndrome measurement
+    assert qc.gates[3].name == "CNOT"
+    assert qc.gates[3].controls == [0] and qc.gates[3].targets[0] == 3
+
+    assert qc.gates[4].name == "CNOT"
+    assert qc.gates[4].controls == [1] and qc.gates[4].targets[0] == 3
+
+    assert qc.gates[5].name == "CNOT"
+    assert qc.gates[5].controls == [1] and qc.gates[5].targets[0] == 4
+
+    assert qc.gates[6].name == "CNOT"
+    assert qc.gates[6].controls == [2] and qc.gates[6].targets[0] == 4
+
+    # Check final three Hadamard gates on data qubits
+    for i in range(3):
+        assert qc.gates[7 + i].name == "SNOT"
+        assert qc.gates[7 + i].targets[0] == i
+
+
+def test_correction_circuit_no_error():
+    """Test correction circuit with no error (syndrome 00)."""
+    qc = PhaseFlipCode.correction_circuit((0, 0))
+    assert qc.N == 3
+    assert len(qc.gates) == 0  # No correction needed
+
+
+def test_correction_circuit_qubit0_error():
+    """Test correction circuit with error on qubit 0 (syndrome 10)."""
+    qc = PhaseFlipCode.correction_circuit((1, 0))
+    assert qc.N == 3
+    assert len(qc.gates) == 1
+    assert qc.gates[0].name == "Z" and qc.gates[0].targets[0] == 0
+
+
+def test_correction_circuit_qubit1_error():
+    """Test correction circuit with error on qubit 1 (syndrome 11)."""
+    qc = PhaseFlipCode.correction_circuit((1, 1))
+    assert qc.N == 3
+    assert len(qc.gates) == 1
+    assert qc.gates[0].name == "Z" and qc.gates[0].targets[0] == 1
+
+
+def test_correction_circuit_qubit2_error():
+    """Test correction circuit with error on qubit 2 (syndrome 01)."""
+    qc = PhaseFlipCode.correction_circuit((0, 1))
+    assert qc.N == 3
+    assert len(qc.gates) == 1
+    assert qc.gates[0].name == "Z" and qc.gates[0].targets[0] == 2
+
+
+def test_decode_circuit_structure():
+    """Test that the decoding circuit has the correct structure."""
+    qc = PhaseFlipCode.decode_circuit()
+
+    # Check circuit has correct number of qubits
+    assert qc.N == 3
+
+    # Check it has the correct number of gates (3 H + 2 CNOT + 1 TOFFOLI + 1 H = 7 gates)
+    assert len(qc.gates) == 7
+
+    # Check first three Hadamard gates
+    for i in range(3):
+        assert qc.gates[i].name == "SNOT"
+        assert qc.gates[i].targets[0] == i
+
+    # Check the two CNOT gates
+    assert qc.gates[3].name == "CNOT"
+    assert qc.gates[3].controls == [0] and qc.gates[3].targets[0] == 2
+
+    assert qc.gates[4].name == "CNOT"
+    assert qc.gates[4].controls == [0] and qc.gates[4].targets[0] == 1
+
+    # Check the TOFFOLI gate
+    assert qc.gates[5].name == "TOFFOLI"
+    assert qc.gates[5].controls == [1, 2] and qc.gates[5].targets[0] == 0
+
+    # Check the final Hadamard gate
+    assert qc.gates[6].name == "SNOT"
+    assert qc.gates[6].targets[0] == 0
diff --git a/tests/test_shor_code.py b/tests/test_shor_code.py
new file mode 100644
index 00000000..24a9cc08
--- /dev/null
+++ b/tests/test_shor_code.py
@@ -0,0 +1,45 @@
+import pytest
+from qutip_qip.algorithms import ShorCode
+
+
+def test_encode_circuit():
+    """Test the Shor code encoding circuit structure."""
+    qc = ShorCode.encode_circuit()
+
+    # Check correct number of qubits
+    assert qc.N == 9
+
+    # Check total number of gates (1H + 2CNOT + 3H + 6CNOT = 12 gates)
+    assert len(qc.gates) == 12
+
+    # Check first Hadamard gate (phase-flip encoding starts)
+    assert qc.gates[0].name == "SNOT" and qc.gates[0].targets[0] == 0
+
+    # Check first level CNOTs (create GHZ-like state across blocks)
+    assert qc.gates[1].name == "CNOT"
+    assert qc.gates[1].controls == [0] and qc.gates[1].targets[0] == 3
+    assert qc.gates[2].name == "CNOT"
+    assert qc.gates[2].controls == [0] and qc.gates[2].targets[0] == 6
+
+    # Check three Hadamard gates (complete phase-flip encoding)
+    assert qc.gates[3].name == "SNOT" and qc.gates[3].targets[0] == 0
+    assert qc.gates[4].name == "SNOT" and qc.gates[4].targets[0] == 3
+    assert qc.gates[5].name == "SNOT" and qc.gates[5].targets[0] == 6
+
+    # Check bit-flip encoding CNOTs for first block
+    assert qc.gates[6].name == "CNOT"
+    assert qc.gates[6].controls == [0] and qc.gates[6].targets[0] == 1
+    assert qc.gates[7].name == "CNOT"
+    assert qc.gates[7].controls == [0] and qc.gates[7].targets[0] == 2
+
+    # Check bit-flip encoding CNOTs for second block
+    assert qc.gates[8].name == "CNOT"
+    assert qc.gates[8].controls == [3] and qc.gates[8].targets[0] == 4
+    assert qc.gates[9].name == "CNOT"
+    assert qc.gates[9].controls == [3] and qc.gates[9].targets[0] == 5
+
+    # Check bit-flip encoding CNOTs for third block
+    assert qc.gates[10].name == "CNOT"
+    assert qc.gates[10].controls == [6] and qc.gates[10].targets[0] == 7
+    assert qc.gates[11].name == "CNOT"
+    assert qc.gates[11].controls == [6] and qc.gates[11].targets[0] == 8