diff --git a/jaxtyping/_decorator.py b/jaxtyping/_decorator.py
index db779d8..9fa014c 100644
--- a/jaxtyping/_decorator.py
+++ b/jaxtyping/_decorator.py
@@ -342,6 +342,7 @@ def modify_annotation(ann):
             @ft.wraps(fn)
             def wrapped_fn(*args, **kwargs):  # pyright: ignore
                 bound = signature.bind(*args, **kwargs)
+                bound.apply_defaults()
                 memos = push_shape_memo(bound.arguments)
                 try:
                     return fn(*args, **kwargs)
@@ -410,6 +411,7 @@ def wrapped_fn(*args, **kwargs):
                 # Raise bind-time errors before we do any shape analysis. (I.e. skip
                 # the pointless jaxtyping information for a non-typechecking failure.)
                 bound = param_signature.bind(*args, **kwargs)
+                bound.apply_defaults()
 
                 memos = push_shape_memo(bound.arguments)
                 try:
diff --git a/test/test_decorator.py b/test/test_decorator.py
index c6d3c1f..02fc5d2 100644
--- a/test/test_decorator.py
+++ b/test/test_decorator.py
@@ -117,6 +117,17 @@ def f(x: int, y=1):
     f(1)
 
 
+def test_default_bindings(getkey, jaxtyp, typecheck):
+    @jaxtyp(typecheck)
+    def f(x: int, y: int = 1) -> Float[Array, "x {y}"]:
+        return jr.normal(getkey(), (x, y))
+
+    f(1)
+    f(1, 1)
+    f(1, 0)
+    f(1, 5)
+
+
 class _GlobalFoo:
     pass