diff --git a/src/runestone.jl b/src/runestone.jl
index 9bbd34d..7629541 100644
--- a/src/runestone.jl
+++ b/src/runestone.jl
@@ -283,5 +283,8 @@ function spaces_around_assignments(ctx::Context, node::JuliaSyntax.GreenNode)
     if !(is_assignment(node) && !JuliaSyntax.is_trivia(node))
         return nothing
     end
-    return spaces_around_x(ctx, node, is_assignment)
+    # for-loop nodes are of kind K"=" even when `in` is used so we need to
+    # include K"in" in the predicate too.
+    is_x = x -> is_assignment(x) || JuliaSyntax.kind(x) === K"in"
+    return spaces_around_x(ctx, node, is_x)
 end
diff --git a/test/runtests.jl b/test/runtests.jl
index d612e3d..147dda8 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -136,4 +136,9 @@ end
     @test format_string("a =+ c") == "a = + c"
     # Short form function definitions
     @test format_string("sin(π)=cos(pi)") == "sin(π) = cos(pi)"
+    # For loop nodes are assignment, even when using `in`
+    @test format_string("for i=1:10\nend\n") == "for i = 1 : 10\nend\n"
+    @test format_string("for i  =1:10\nend\n") == "for i = 1 : 10\nend\n"
+    @test format_string("for i  =  1:10\nend\n") == "for i = 1 : 10\nend\n"
+    @test format_string("for i  in  1:10\nend\n") == "for i in 1 : 10\nend\n"
 end