diff --git a/src/ComposableExpression.jl b/src/ComposableExpression.jl
index 0666e1bb5..185e6e5cf 100644
--- a/src/ComposableExpression.jl
+++ b/src/ComposableExpression.jl
@@ -372,7 +372,7 @@ function Base.literal_pow(::typeof(^), x::ValidVector, ::Val{p}) where {p}
 end
 
 for op in (
-    :sin, :cos, :tan, :sinh, :cosh, :tanh, :asin, :acos,
+    :sin, :cos, :tan, :sinh, :cosh, :tanh, :asin, :acos, :atan,
     :asinh, :acosh, :atanh, :sec, :csc, :cot, :asec, :acsc, :acot, :sech, :csch,
     :coth, :asech, :acsch, :acoth, :sinc, :cosc, :cosd, :cotd, :cscd, :secd,
     :sinpi, :cospi, :sind, :tand, :acosd, :acotd, :acscd, :asecd, :asind,
diff --git a/test/test_composable_expression.jl b/test/test_composable_expression.jl
index a67a8a03c..1db032fd1 100644
--- a/test/test_composable_expression.jl
+++ b/test/test_composable_expression.jl
@@ -94,9 +94,13 @@ end
     # Test unary operations on ValidVector
     @test sin(x).x ≈ sin.([1.0, 2.0, 3.0])
     @test cos(x).x ≈ cos.([1.0, 2.0, 3.0])
+    @test atan(x).x ≈ atan.([1.0, 2.0, 3.0])
     @test abs(x).x ≈ [1.0, 2.0, 3.0]
     @test (-x).x ≈ [-1.0, -2.0, -3.0]
 
+    # Test binary atan (atan2)
+    @test atan(y, x).x ≈ atan.([0.0, 2.0, 4.0], [1.0, 2.0, 3.0])
+
     # Test propagation of invalid flag
     invalid_x = ValidVector([1.0, 2.0, 3.0], false)
     @test !((invalid_x + 2.0).valid)