diff --git a/gradle.properties b/gradle.properties
index a99c6707..2d53922b 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -1,5 +1,5 @@
 # Version of buf.build/bufbuild/protovalidate to use.
-protovalidate.version = v0.13.1
+protovalidate.version = v0.13.3
 
 # Arguments to the protovalidate-conformance CLI
 protovalidate.conformance.args = --strict_message --strict_error --expected_failures=expected-failures.yaml
diff --git a/src/main/java/build/buf/protovalidate/EvaluatorBuilder.java b/src/main/java/build/buf/protovalidate/EvaluatorBuilder.java
index 5e266f93..2e62e062 100644
--- a/src/main/java/build/buf/protovalidate/EvaluatorBuilder.java
+++ b/src/main/java/build/buf/protovalidate/EvaluatorBuilder.java
@@ -180,7 +180,7 @@ private void buildMessage(Descriptor desc, MessageEvaluator msgEval)
         processMessageExpressions(descriptor, msgRules, msgEval, defaultInstance);
         processMessageOneofRules(descriptor, msgRules, msgEval);
         processOneofRules(descriptor, msgEval);
-        processFields(descriptor, msgEval);
+        processFields(descriptor, msgRules, msgEval);
       } catch (InvalidProtocolBufferException e) {
         throw new CompilationException(
             "failed to parse proto definition: " + desc.getFullName(), e);
@@ -243,12 +243,17 @@ private void processOneofRules(Descriptor desc, MessageEvaluator msgEval)
       }
     }
 
-    private void processFields(Descriptor desc, MessageEvaluator msgEval)
+    private void processFields(Descriptor desc, MessageRules msgRules, MessageEvaluator msgEval)
         throws CompilationException, InvalidProtocolBufferException {
       List<FieldDescriptor> fields = desc.getFields();
       for (FieldDescriptor fieldDescriptor : fields) {
         FieldDescriptor descriptor = desc.findFieldByName(fieldDescriptor.getName());
         FieldRules fieldRules = resolver.resolveFieldRules(descriptor);
+        if (!fieldRules.hasIgnore()
+            && msgRules.getOneofList().stream()
+                .anyMatch(oneof -> oneof.getFieldsList().contains(fieldDescriptor.getName()))) {
+          fieldRules = fieldRules.toBuilder().setIgnore(Ignore.IGNORE_IF_UNPOPULATED).build();
+        }
         FieldEvaluator fldEval = buildField(descriptor, fieldRules);
         msgEval.append(fldEval);
       }
diff --git a/src/main/resources/buf/validate/validate.proto b/src/main/resources/buf/validate/validate.proto
index a4377c5b..8a0e0b44 100644
--- a/src/main/resources/buf/validate/validate.proto
+++ b/src/main/resources/buf/validate/validate.proto
@@ -156,6 +156,9 @@ message MessageRules {
   //      silently ignored when unmarshalling, with only the last field being set when
   //      unmarshalling completes.
   //
+  // Note that adding a field to a `oneof` will also set the IGNORE_IF_UNPOPULATED on the fields. This means
+  // only the field that is set will be validated and the unset fields are not validated according to the field rules.
+  // This behavior can be overridden by setting `ignore` against a field.
   //
   // ```proto
   // message MyMessage {