diff --git a/flax/linen/normalization.py b/flax/linen/normalization.py
index 10fa22264..f37369e38 100644
--- a/flax/linen/normalization.py
+++ b/flax/linen/normalization.py
@@ -300,7 +300,13 @@ class BatchNorm(Module):
   use_fast_variance: bool = True
 
   @compact
-  def __call__(self, x, use_running_average: Optional[bool] = None, mask=None):
+  def __call__(
+      self,
+      x,
+      use_running_average: Optional[bool] = None,
+      *,
+      mask: Optional[jax.Array] = None,
+  ):
     """Normalizes the input using batch statistics.
 
     NOTE:
@@ -449,7 +455,7 @@ class LayerNorm(Module):
   use_fast_variance: bool = True
 
   @compact
-  def __call__(self, x, mask=None):
+  def __call__(self, x, *, mask: Optional[jax.Array] = None):
     """Applies layer normalization on the input.
 
     Args:
@@ -543,7 +549,7 @@ class RMSNorm(Module):
   axis_index_groups: Any = None
 
   @compact
-  def __call__(self, x, mask=None):
+  def __call__(self, x, *, mask: Optional[jax.Array] = None):
     """Applies RMS layer normalization on the input.
 
     Args:
@@ -664,7 +670,7 @@ class GroupNorm(Module):
   use_fast_variance: bool = True
 
   @compact
-  def __call__(self, x, mask=None):
+  def __call__(self, x, *, mask: Optional[jax.Array] = None):
     """Applies group normalization to the input (arxiv.org/abs/1803.08494).
 
     Args:
@@ -834,7 +840,7 @@ class InstanceNorm(Module):
   use_fast_variance: bool = True
 
   @compact
-  def __call__(self, x, mask=None):
+  def __call__(self, x, *, mask: Optional[jax.Array] = None):
     """Applies instance normalization on the input.
 
     Args:
diff --git a/tests/linen/linen_test.py b/tests/linen/linen_test.py
index 9af329018..d3184e2c4 100644
--- a/tests/linen/linen_test.py
+++ b/tests/linen/linen_test.py
@@ -146,7 +146,7 @@ def test_layer_norm_mask(self):
     x = jnp.where(m, x, jnp.nan)
 
     module = nn.LayerNorm()
-    y, w = module.init_with_output(key, x, m)
+    y, w = module.init_with_output(key, x, mask=m)
 
     z = y.mean(-1, where=m)
     np.testing.assert_allclose(z, 0, atol=1e-4)
@@ -163,7 +163,7 @@ def test_rms_norm_mask(self):
     x = jnp.where(m, x, jnp.nan)
 
     module = nn.RMSNorm()
-    y, w = module.init_with_output(key, x, m)
+    y, w = module.init_with_output(key, x, mask=m)
 
     z = np.square(y).mean(-1, where=m)
     np.testing.assert_allclose(z, 1, atol=1e-4)
@@ -177,7 +177,7 @@ def test_group_norm_mask(self):
     x = jnp.where(m, x, jnp.nan)
 
     module = nn.GroupNorm(7, use_bias=False, use_scale=False)
-    y, w = module.init_with_output(key, x, m)
+    y, w = module.init_with_output(key, x, mask=m)
 
     yr = y.reshape((13, 3, 5, 7, 11))
     mr = m.reshape((13, 3, 5, 7, 11))