diff --git a/torchvision/models/mnasnet.py b/torchvision/models/mnasnet.py
index 6f403fb5e30..b1da02f4697 100644
--- a/torchvision/models/mnasnet.py
+++ b/torchvision/models/mnasnet.py
@@ -235,8 +235,20 @@ class MNASNet0_5_Weights(WeightsEnum):
 
 
 class MNASNet0_75_Weights(WeightsEnum):
-    # If a default model is added here the corresponding changes need to be done in mnasnet0_75
-    pass
+    IMAGENET1K_V1 = Weights(
+        url="https://download.pytorch.org/models/mnasnet0_75-7090bc5f.pth",
+        transforms=partial(ImageClassification, crop_size=224, resize_size=232),
+        meta={
+            **_COMMON_META,
+            "recipe": "https://github.com/pytorch/vision/pull/6019",
+            "num_params": 3170208,
+            "metrics": {
+                "acc@1": 71.180,
+                "acc@5": 90.496,
+            },
+        },
+    )
+    DEFAULT = IMAGENET1K_V1
 
 
 class MNASNet1_0_Weights(WeightsEnum):
@@ -256,8 +268,20 @@ class MNASNet1_0_Weights(WeightsEnum):
 
 
 class MNASNet1_3_Weights(WeightsEnum):
-    # If a default model is added here the corresponding changes need to be done in mnasnet1_3
-    pass
+    IMAGENET1K_V1 = Weights(
+        url="https://download.pytorch.org/models/mnasnet1_3-a4c69d6f.pth",
+        transforms=partial(ImageClassification, crop_size=224, resize_size=232),
+        meta={
+            **_COMMON_META,
+            "recipe": "https://github.com/pytorch/vision/pull/6019",
+            "num_params": 6282256,
+            "metrics": {
+                "acc@1": 76.506,
+                "acc@5": 93.522,
+            },
+        },
+    )
+    DEFAULT = IMAGENET1K_V1
 
 
 def _mnasnet(alpha: float, weights: Optional[WeightsEnum], progress: bool, **kwargs: Any) -> MNASNet:
@@ -299,15 +323,17 @@ def mnasnet0_5(*, weights: Optional[MNASNet0_5_Weights] = None, progress: bool =
     return _mnasnet(0.5, weights, progress, **kwargs)
 
 
-@handle_legacy_interface(weights=("pretrained", None))
+@handle_legacy_interface(weights=("pretrained", MNASNet0_75_Weights.IMAGENET1K_V1))
 def mnasnet0_75(*, weights: Optional[MNASNet0_75_Weights] = None, progress: bool = True, **kwargs: Any) -> MNASNet:
     """MNASNet with depth multiplier of 0.75 from
     `MnasNet: Platform-Aware Neural Architecture Search for Mobile
     <https://arxiv.org/pdf/1807.11626.pdf>`_ paper.
 
     Args:
-        weights (:class:`~torchvision.models.MNASNet0_75_Weights`, optional): Currently
-            no pre-trained weights are available and by default no pre-trained
+        weights (:class:`~torchvision.models.MNASNet0_75_Weights`, optional): The
+            pretrained weights to use. See
+            :class:`~torchvision.models.MNASNet0_75_Weights` below for
+            more details, and possible values. By default, no pre-trained
             weights are used.
         progress (bool, optional): If True, displays a progress bar of the
             download to stderr. Default is True.
@@ -351,15 +377,17 @@ def mnasnet1_0(*, weights: Optional[MNASNet1_0_Weights] = None, progress: bool =
     return _mnasnet(1.0, weights, progress, **kwargs)
 
 
-@handle_legacy_interface(weights=("pretrained", None))
+@handle_legacy_interface(weights=("pretrained", MNASNet1_3_Weights.IMAGENET1K_V1))
 def mnasnet1_3(*, weights: Optional[MNASNet1_3_Weights] = None, progress: bool = True, **kwargs: Any) -> MNASNet:
     """MNASNet with depth multiplier of 1.3 from
     `MnasNet: Platform-Aware Neural Architecture Search for Mobile
     <https://arxiv.org/pdf/1807.11626.pdf>`_ paper.
 
     Args:
-        weights (:class:`~torchvision.models.MNASNet1_3_Weights`, optional): Currently
-            no pre-trained weights are available and by default no pre-trained
+        weights (:class:`~torchvision.models.MNASNet1_3_Weights`, optional): The
+            pretrained weights to use. See
+            :class:`~torchvision.models.MNASNet1_3_Weights` below for
+            more details, and possible values. By default, no pre-trained
             weights are used.
         progress (bool, optional): If True, displays a progress bar of the
             download to stderr. Default is True.