diff --git a/src/tridiag.jl b/src/tridiag.jl
index 0e8a5119..02b4c352 100644
--- a/src/tridiag.jl
+++ b/src/tridiag.jl
@@ -174,16 +174,13 @@ end
 isreal(S::SymTridiagonal) = isreal(S.dv) && isreal(S.ev)
 
 transpose(S::SymTridiagonal) = S
-adjoint(S::SymTridiagonal{<:Number}) = SymTridiagonal(vec(adjoint(S.dv)), vec(adjoint(S.ev)))
-adjoint(S::SymTridiagonal{<:Number, <:Base.ReshapedArray{<:Number,1,<:Adjoint}}) =
-    SymTridiagonal(adjoint(parent(S.dv)), adjoint(parent(S.ev)))
+adjoint(S::SymTridiagonal) = SymTridiagonal(_vecadjoint(S.dv), _vecadjoint(S.ev))
 
 permutedims(S::SymTridiagonal) = S
 function permutedims(S::SymTridiagonal, perm)
     Base.checkdims_perm(axes(S), axes(S), perm)
     NTuple{2}(perm) == (2, 1) ? permutedims(S) : S
 end
-Base.copy(S::Adjoint{<:Any,<:SymTridiagonal}) = SymTridiagonal(map(x -> copy.(adjoint.(x)), (S.parent.dv, S.parent.ev))...)
 
 ishermitian(S::SymTridiagonal) = isreal(S.dv) && isreal(_evview(S))
 issymmetric(S::SymTridiagonal) = true
@@ -683,23 +680,17 @@ for func in (:conj, :copy, :real, :imag)
 end
 isreal(T::Tridiagonal) = isreal(T.dl) && isreal(T.d) && isreal(T.du)
 
-adjoint(S::Tridiagonal{<:Number}) = Tridiagonal(vec(adjoint(S.du)), vec(adjoint(S.d)), vec(adjoint(S.dl)))
-adjoint(S::Tridiagonal{<:Number, <:Base.ReshapedArray{<:Number,1,<:Adjoint}}) =
-    Tridiagonal(adjoint(parent(S.du)), adjoint(parent(S.d)), adjoint(parent(S.dl)))
-transpose(S::Tridiagonal{<:Number}) = Tridiagonal(S.du, S.d, S.dl)
+adjoint(S::Tridiagonal) = Tridiagonal(_vecadjoint(S.du), _vecadjoint(S.d), _vecadjoint(S.dl))
+transpose(S::Tridiagonal) = Tridiagonal(_vectranspose(S.du), _vectranspose(S.d), _vectranspose(S.dl))
 permutedims(T::Tridiagonal) = Tridiagonal(T.du, T.d, T.dl)
 function permutedims(T::Tridiagonal, perm)
     Base.checkdims_perm(axes(T), axes(T), perm)
     NTuple{2}(perm) == (2, 1) ? permutedims(T) : T
 end
-Base.copy(aS::Adjoint{<:Any,<:Tridiagonal}) = (S = aS.parent; Tridiagonal(map(x -> copy.(adjoint.(x)), (S.du, S.d, S.dl))...))
-Base.copy(tS::Transpose{<:Any,<:Tridiagonal}) = (S = tS.parent; Tridiagonal(map(x -> copy.(transpose.(x)), (S.du, S.d, S.dl))...))
 
 ishermitian(S::Tridiagonal) = all(ishermitian, S.d) && all(Iterators.map((x, y) -> x == y', S.du, S.dl))
 issymmetric(S::Tridiagonal) = all(issymmetric, S.d) && all(Iterators.map((x, y) -> x == transpose(y), S.du, S.dl))
 
-\(A::Adjoint{<:Any,<:Tridiagonal}, B::Adjoint{<:Any,<:AbstractVecOrMat}) = copy(A) \ B
-
 function diag(M::Tridiagonal, n::Integer=0)
     # every branch call similar(..., ::Int) to make sure the
     # same vector type is returned independent of n
diff --git a/test/tridiag.jl b/test/tridiag.jl
index effea2b0..7eaa4128 100644
--- a/test/tridiag.jl
+++ b/test/tridiag.jl
@@ -1207,4 +1207,26 @@ end
     @test_throws BoundsError S[LinearAlgebra.BandIndex(0,size(S,1)+1)]
 end
 
+@testset "lazy adjtrans" begin
+    dv = fill([1 2; 3 4], 3)
+    ev = fill([5 6; 7 8], 2)
+    T = Tridiagonal(ev, dv, ev)
+    S = SymTridiagonal(dv, ev)
+    m = [2 4; 4 2]
+    for B in (copy(T), copy(S))
+        for op in (transpose, adjoint)
+            C = op(B)
+            el = op(m)
+            C[1,1] = el
+            @test B[1,1] == m
+            if B isa Tridiagonal
+                C[2,1] = el
+                @test B[1,2] == m
+            end
+            @test (@allocated op(B)) == 0
+            @test (@allocated op(op(B))) == 0
+        end
+    end
+end
+
 end # module TestTridiagonal