diff --git a/ethosu/vela/supported_operators.py b/ethosu/vela/supported_operators.py
index 84432c7..8b759be 100644
--- a/ethosu/vela/supported_operators.py
+++ b/ethosu/vela/supported_operators.py
@@ -252,6 +252,7 @@
 
         # FullyConnected specific checks:
         self.specific_constraints[Op.FullyConnected].append(SupportedOperators.constraint_fc_output_2d)
+        self.specific_constraints[Op.FullyConnected].append(SupportedOperators.constraint_keep_dim_ifm_ofm)
 
         # Pad specific checks:
         self.specific_constraints[Op.Pad].append(SupportedOperators.constraint_matching_in_out_types)
@@ -1068,3 +1069,11 @@
         alpha = op.attrs["alpha"]
         valid = alpha >= 0
         return valid, f"Op has alpha={alpha}"
+
+    @staticmethod
+    def constraint_keep_dim_ifm_ofm(op):
+        "The IFM and OFM must have the same number of dimensions if keep_num_dims is set to true"
+        valid = True
+        if op.attrs.get("keep_num_dims"):
+            valid = len(op.ifm.shape) == len(op.ofm.shape)
+        return valid, f"Op has ifm shape={op.ifm.shape} and ofm shape={op.ofm.shape}"
diff --git a/ethosu/vela/test/test_supported_operators.py b/ethosu/vela/test/test_supported_operators.py
index 6401d29..832d60f 100644
--- a/ethosu/vela/test/test_supported_operators.py
+++ b/ethosu/vela/test/test_supported_operators.py
@@ -945,3 +945,11 @@
     out_tens = Tensor([1, 8, 8, 8], DataType.uint8, "out")
     op = testutil.create_op(Op.HardSwish, [in_tens], out_tens)
     assert not support.is_operator_supported(op)
+
+
+def test_constraint_keep_dims_ifm_ofm():
+    op = testutil.create_op_with_quant_tensors(Op.FullyConnected, [4, 8, 8, 4], [32, 32], weights_shape=[4, 8, 8, 4])
+    op.attrs["keep_num_dims"] = True
+    assert not support.is_operator_supported(op)
+    op.attrs["keep_num_dims"] = False
+    assert support.is_operator_supported(op)
diff --git a/ethosu/vela/tflite_mapping.py b/ethosu/vela/tflite_mapping.py
index 40e3090..41d57c0 100644
--- a/ethosu/vela/tflite_mapping.py
+++ b/ethosu/vela/tflite_mapping.py
@@ -501,7 +501,9 @@
     BuiltinOperator.FLOOR: (Op.Floor, None),
     BuiltinOperator.FULLY_CONNECTED: (
         Op.FullyConnected,
-        OptionsSerializer("FullyConnectedOptions", (fused_act, "weights_format", "asymmetric_quantize_inputs")),
+        OptionsSerializer(
+            "FullyConnectedOptions", (fused_act, "weights_format", "asymmetric_quantize_inputs", "keep_num_dims")
+        ),
     ),
     BuiltinOperator.HASHTABLE_LOOKUP: (Op.HashtableLookup, None),
     BuiltinOperator.L2_NORMALIZATION: (Op.L2Norm, OptionsSerializer("L2NormOptions", (fused_act,))),
@@ -618,7 +620,7 @@
     BuiltinOperator.EQUAL: (Op.Equal, OptionsSerializer("EqualOptions")),
     BuiltinOperator.NOT_EQUAL: (Op.NotEqual, OptionsSerializer("NotEqualOptions")),
     BuiltinOperator.LOG: (Op.Log, None),
-    BuiltinOperator.SUM: (Op.Sum, None),
+    BuiltinOperator.SUM: (Op.Sum, reducer_opts),
     BuiltinOperator.SQRT: (Op.Sqrt, None),
     BuiltinOperator.RSQRT: (Op.Rsqrt, None),
     BuiltinOperator.SHAPE: (