diff --git a/CHANGELOG.md b/CHANGELOG.md
index df34c93..8366cb7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@ All notable changes to diffly are documented here. The format follows [Keep a Ch
 ### Fixed
 
 - Fast keystroke bursts in the interactive review menu register every press: escape sequences stop at their terminator instead of swallowing neighboring keys.
+- `diffly setup` no longer runs the update check twice in a row (once in `main()` and again inside the wizard it launches).
 - Pressing an arrow key in the interactive review menu no longer crashes with `NameError: name '_read_escape_sequence' is not defined`; the escape-sequence reader is defined again and a lone Escape still exits without blocking.
 
 ## [1.0.0] - 2026-08-22
diff --git a/src/diffly_cli/cli.py b/src/diffly_cli/cli.py
index 20f4bcf..752a989 100644
--- a/src/diffly_cli/cli.py
+++ b/src/diffly_cli/cli.py
@@ -907,7 +907,9 @@ def main(argv: list[str] | None = None) -> int:
     if not effective_argv:
         return run_wizard(parser)
     args = parser.parse_args(effective_argv)
-    if args.command not in ("update", "version", "help", "doctor"):
+    # `setup` ends in the wizard, which runs its own update check; checking
+    # here too would prompt the user twice in a row.
+    if args.command not in ("update", "version", "help", "doctor", "setup"):
         _check_and_prompt_update()
     return args.func(args)
 
diff --git a/tests/test_regressions.py b/tests/test_regressions.py
index d51d481..1cf6c85 100644
--- a/tests/test_regressions.py
+++ b/tests/test_regressions.py
@@ -398,3 +398,20 @@ def test_escape_sequence_reader_consumes_exactly_one_sequence(monkeypatch):
     finally:
         os.close(read_fd)
         os.close(write_fd)
+
+
+def test_setup_delegates_the_update_check_to_the_wizard(monkeypatch):
+    """Regression: `diffly setup` used to run the update check twice — once in
+    main() and again inside the wizard it launches — prompting back to back."""
+    import diffly_cli.cli as cli
+
+    calls: list[str] = []
+    monkeypatch.setattr(cli, "_check_and_prompt_update", lambda: calls.append("check"))
+    monkeypatch.setattr(cli, "run_setup", lambda args: 0)
+    assert cli.main(["setup"]) == 0
+    assert calls == []
+
+    calls.clear()
+    monkeypatch.setattr(cli, "run_pr", lambda args: 0)
+    assert cli.main(["pr", "acme/demo", "1"]) == 0
+    assert calls == ["check"]