diff --git a/optimum/exporters/onnx/model_configs.py b/optimum/exporters/onnx/model_configs.py
index 496957b2b5d..d4c4ac934b9 100644
--- a/optimum/exporters/onnx/model_configs.py
+++ b/optimum/exporters/onnx/model_configs.py
@@ -981,7 +981,7 @@ class UNetOnnxConfig(VisionOnnxConfig):
     @property
     def inputs(self) -> Dict[str, Dict[int, str]]:
         common_inputs = {
-            "sample": {0: "batch_size", 1: "num_channels", 2: "height", 3: "width"},
+            "sample": {0: "batch_size", 2: "height", 3: "width"},
             "timestep": {0: "steps"},
             "encoder_hidden_states": {0: "batch_size", 1: "sequence_length"},
         }
@@ -998,7 +998,7 @@ def inputs(self) -> Dict[str, Dict[int, str]]:
     @property
     def outputs(self) -> Dict[str, Dict[int, str]]:
         return {
-            "out_sample": {0: "batch_size", 1: "num_channels", 2: "height", 3: "width"},
+            "out_sample": {0: "batch_size", 2: "height", 3: "width"},
         }
 
     @property
@@ -1045,13 +1045,13 @@ class VaeEncoderOnnxConfig(VisionOnnxConfig):
     @property
     def inputs(self) -> Dict[str, Dict[int, str]]:
         return {
-            "sample": {0: "batch_size", 1: "num_channels", 2: "height", 3: "width"},
+            "sample": {0: "batch_size", 2: "height", 3: "width"},
         }
 
     @property
     def outputs(self) -> Dict[str, Dict[int, str]]:
         return {
-            "latent_sample": {0: "batch_size", 1: "num_channels_latent", 2: "height_latent", 3: "width_latent"},
+            "latent_sample": {0: "batch_size", 2: "height_latent", 3: "width_latent"},
         }
 
 
@@ -1069,13 +1069,13 @@ class VaeDecoderOnnxConfig(VisionOnnxConfig):
     @property
     def inputs(self) -> Dict[str, Dict[int, str]]:
         return {
-            "latent_sample": {0: "batch_size", 1: "num_channels_latent", 2: "height_latent", 3: "width_latent"},
+            "latent_sample": {0: "batch_size", 2: "height_latent", 3: "width_latent"},
         }
 
     @property
     def outputs(self) -> Dict[str, Dict[int, str]]:
         return {
-            "sample": {0: "batch_size", 1: "num_channels", 2: "height", 3: "width"},
+            "sample": {0: "batch_size", 2: "height", 3: "width"},
         }