diff --git a/tests/unit/ast/nodes/test_hex.py b/tests/unit/ast/nodes/test_hex.py
index 1b61764d574..7168defa99d 100644
--- a/tests/unit/ast/nodes/test_hex.py
+++ b/tests/unit/ast/nodes/test_hex.py
@@ -33,6 +33,9 @@ def foo():
     """
 foo: constant(bytes4) = 0x12_34_56
     """,
+    """
+foo: constant(bytes4) = 0X12345678
+    """,
 ]
 
 
diff --git a/vyper/ast/nodes.py b/vyper/ast/nodes.py
index f4c99b7952d..991edeca6ee 100644
--- a/vyper/ast/nodes.py
+++ b/vyper/ast/nodes.py
@@ -854,10 +854,15 @@ class Hex(Constant):
 
     def validate(self):
         if "_" in self.value:
+            # TODO: revisit this, we should probably allow underscores
             raise InvalidLiteral("Underscores not allowed in hex literals", self)
         if len(self.value) % 2:
             raise InvalidLiteral("Hex notation requires an even number of digits", self)
 
+        if self.value.startswith("0X"):
+            hint = f"Did you mean `0x{self.value[2:]}`?"
+            raise InvalidLiteral("Hex literal begins with 0X!", self, hint=hint)
+
     @property
     def n_nibbles(self):
         """