diff --git a/shared/sx/ref/eval.sx b/shared/sx/ref/eval.sx
index ccc1a8d..7d3b5e9 100644
--- a/shared/sx/ref/eval.sx
+++ b/shared/sx/ref/eval.sx
@@ -632,18 +632,26 @@
 ;; 7. Higher-order forms
 ;; --------------------------------------------------------------------------
 
+;; call-fn: unified caller for HO forms — handles both Lambda and native callable
+(define call-fn
+  (fn (f args env)
+    (cond
+      (lambda? f)   (trampoline (call-lambda f args env))
+      (callable? f) (apply f args)
+      :else         (error (str "Not callable in HO form: " (inspect f))))))
+
 (define ho-map
   (fn (args env)
     (let ((f    (trampoline (eval-expr (first args) env)))
           (coll (trampoline (eval-expr (nth args 1) env))))
-      (map (fn (item) (trampoline (call-lambda f (list item) env))) coll))))
+      (map (fn (item) (call-fn f (list item) env)) coll))))
 
 (define ho-map-indexed
   (fn (args env)
     (let ((f    (trampoline (eval-expr (first args) env)))
           (coll (trampoline (eval-expr (nth args 1) env))))
       (map-indexed
-        (fn (i item) (trampoline (call-lambda f (list i item) env)))
+        (fn (i item) (call-fn f (list i item) env))
         coll))))
 
 (define ho-filter
@@ -651,7 +659,7 @@
     (let ((f    (trampoline (eval-expr (first args) env)))
           (coll (trampoline (eval-expr (nth args 1) env))))
       (filter
-        (fn (item) (trampoline (call-lambda f (list item) env)))
+        (fn (item) (call-fn f (list item) env))
         coll))))
 
 (define ho-reduce
@@ -660,7 +668,7 @@
           (init (trampoline (eval-expr (nth args 1) env)))
           (coll (trampoline (eval-expr (nth args 2) env))))
       (reduce
-        (fn (acc item) (trampoline (call-lambda f (list acc item) env)))
+        (fn (acc item) (call-fn f (list acc item) env))
         init
         coll))))
 
@@ -669,7 +677,7 @@
     (let ((f    (trampoline (eval-expr (first args) env)))
           (coll (trampoline (eval-expr (nth args 1) env))))
       (some
-        (fn (item) (trampoline (call-lambda f (list item) env)))
+        (fn (item) (call-fn f (list item) env))
         coll))))
 
 (define ho-every
@@ -677,7 +685,7 @@
     (let ((f    (trampoline (eval-expr (first args) env)))
           (coll (trampoline (eval-expr (nth args 1) env))))
       (every?
-        (fn (item) (trampoline (call-lambda f (list item) env)))
+        (fn (item) (call-fn f (list item) env))
         coll))))
 
 
@@ -686,7 +694,7 @@
     (let ((f    (trampoline (eval-expr (first args) env)))
           (coll (trampoline (eval-expr (nth args 1) env))))
       (for-each
-        (fn (item) (trampoline (call-lambda f (list item) env)))
+        (fn (item) (call-fn f (list item) env))
         coll))))
 
 
diff --git a/shared/sx/ref/sx_ref.py b/shared/sx/ref/sx_ref.py
index dfac72f..a11f98e 100644
--- a/shared/sx/ref/sx_ref.py
+++ b/shared/sx/ref/sx_ref.py
@@ -968,26 +968,29 @@ sf_set_bang = lambda args, env: (lambda name: (lambda value: _sx_begin(_sx_dict_
 # expand-macro
 expand_macro = lambda mac, raw_args, env: (lambda local: _sx_begin(for_each(lambda pair: _sx_dict_set(local, first(pair), (nth(raw_args, nth(pair, 1)) if sx_truthy((nth(pair, 1) < len(raw_args))) else NIL)), map_indexed(lambda i, p: [p, i], macro_params(mac))), (_sx_dict_set(local, macro_rest_param(mac), slice(raw_args, len(macro_params(mac)))) if sx_truthy(macro_rest_param(mac)) else NIL), trampoline(eval_expr(macro_body(mac), local))))(env_merge(macro_closure(mac), env))
 
+# call-fn
+call_fn = lambda f, args, env: (trampoline(call_lambda(f, args, env)) if sx_truthy(is_lambda(f)) else (apply(f, args) if sx_truthy(is_callable(f)) else error(sx_str('Not callable in HO form: ', inspect(f)))))
+
 # ho-map
-ho_map = lambda args, env: (lambda f: (lambda coll: map(lambda item: trampoline(call_lambda(f, [item], env)), coll))(trampoline(eval_expr(nth(args, 1), env))))(trampoline(eval_expr(first(args), env)))
+ho_map = lambda args, env: (lambda f: (lambda coll: map(lambda item: call_fn(f, [item], env), coll))(trampoline(eval_expr(nth(args, 1), env))))(trampoline(eval_expr(first(args), env)))
 
 # ho-map-indexed
-ho_map_indexed = lambda args, env: (lambda f: (lambda coll: map_indexed(lambda i, item: trampoline(call_lambda(f, [i, item], env)), coll))(trampoline(eval_expr(nth(args, 1), env))))(trampoline(eval_expr(first(args), env)))
+ho_map_indexed = lambda args, env: (lambda f: (lambda coll: map_indexed(lambda i, item: call_fn(f, [i, item], env), coll))(trampoline(eval_expr(nth(args, 1), env))))(trampoline(eval_expr(first(args), env)))
 
 # ho-filter
-ho_filter = lambda args, env: (lambda f: (lambda coll: filter(lambda item: trampoline(call_lambda(f, [item], env)), coll))(trampoline(eval_expr(nth(args, 1), env))))(trampoline(eval_expr(first(args), env)))
+ho_filter = lambda args, env: (lambda f: (lambda coll: filter(lambda item: call_fn(f, [item], env), coll))(trampoline(eval_expr(nth(args, 1), env))))(trampoline(eval_expr(first(args), env)))
 
 # ho-reduce
-ho_reduce = lambda args, env: (lambda f: (lambda init: (lambda coll: reduce(lambda acc, item: trampoline(call_lambda(f, [acc, item], env)), init, coll))(trampoline(eval_expr(nth(args, 2), env))))(trampoline(eval_expr(nth(args, 1), env))))(trampoline(eval_expr(first(args), env)))
+ho_reduce = lambda args, env: (lambda f: (lambda init: (lambda coll: reduce(lambda acc, item: call_fn(f, [acc, item], env), init, coll))(trampoline(eval_expr(nth(args, 2), env))))(trampoline(eval_expr(nth(args, 1), env))))(trampoline(eval_expr(first(args), env)))
 
 # ho-some
-ho_some = lambda args, env: (lambda f: (lambda coll: some(lambda item: trampoline(call_lambda(f, [item], env)), coll))(trampoline(eval_expr(nth(args, 1), env))))(trampoline(eval_expr(first(args), env)))
+ho_some = lambda args, env: (lambda f: (lambda coll: some(lambda item: call_fn(f, [item], env), coll))(trampoline(eval_expr(nth(args, 1), env))))(trampoline(eval_expr(first(args), env)))
 
 # ho-every
-ho_every = lambda args, env: (lambda f: (lambda coll: every_p(lambda item: trampoline(call_lambda(f, [item], env)), coll))(trampoline(eval_expr(nth(args, 1), env))))(trampoline(eval_expr(first(args), env)))
+ho_every = lambda args, env: (lambda f: (lambda coll: every_p(lambda item: call_fn(f, [item], env), coll))(trampoline(eval_expr(nth(args, 1), env))))(trampoline(eval_expr(first(args), env)))
 
 # ho-for-each
-ho_for_each = lambda args, env: (lambda f: (lambda coll: for_each(lambda item: trampoline(call_lambda(f, [item], env)), coll))(trampoline(eval_expr(nth(args, 1), env))))(trampoline(eval_expr(first(args), env)))
+ho_for_each = lambda args, env: (lambda f: (lambda coll: for_each(lambda item: call_fn(f, [item], env), coll))(trampoline(eval_expr(nth(args, 1), env))))(trampoline(eval_expr(first(args), env)))
 
 
 # === Transpiled from forms (server definition forms) ===
diff --git a/shared/sx/tests/test_sx_ref.py b/shared/sx/tests/test_sx_ref.py
index ae21015..8e0fa80 100644
--- a/shared/sx/tests/test_sx_ref.py
+++ b/shared/sx/tests/test_sx_ref.py
@@ -384,6 +384,29 @@ class TestDefhandler:
         assert adef.params == ["title", "body"]
 
 
+class TestHOWithNativeCallable:
+    def test_map_with_native_fn(self):
+        """map should work with native callables (primitives), not just Lambda."""
+        result = ev('(map str (list 1 2 3))')
+        assert result == ["1", "2", "3"]
+
+    def test_filter_with_native_fn(self):
+        result = ev('(filter number? (list 1 "a" 2 "b" 3))')
+        assert result == [1, 2, 3]
+
+    def test_map_with_env_fn(self):
+        """map should work with Python functions registered in env."""
+        env = {"double": lambda x: x * 2}
+        result = ev('(map double (list 1 2 3))', env)
+        assert result == [2, 4, 6]
+
+    def test_ho_non_callable_fails_fast(self):
+        """Passing a non-callable to map should error clearly."""
+        import pytest
+        with pytest.raises(sx_ref.EvalError, match="Not callable"):
+            ev('(map 42 (list 1 2 3))')
+
+
 class TestMacros:
     def test_defmacro_and_expand(self):
         env = {}