diff --git a/Makefile b/Makefile
index c3b5e27..5d7fd9d 100644
--- a/Makefile
+++ b/Makefile
@@ -19,7 +19,7 @@ build: install-deps
 run:
 	rm -fr $(OUTPUTDIR)
 	mkdir -p $(OUTPUTDIR)
-	protoc --plugin=./$(BINDIR)/protoc-gen-openapi --openapi_out=single_file=true,use_ref=true:$(OUTPUTDIR)/. -Itestdata testdata/testpkg/test1.proto testdata/testpkg/test2.proto testdata/testpkg/test6.proto testdata/testpkg2/test3.proto
+	protoc --plugin=./$(BINDIR)/protoc-gen-openapi --openapi_out=single_file=true,use_ref=true:$(OUTPUTDIR)/. -Itestdata testdata/testpkg/test1.proto testdata/testpkg/test2.proto testdata/testpkg/test6.proto testdata/testpkg2/test3.proto testdata/testpkg/test_proto3_optional.proto
 
 gotest:
 	PATH=$(BINDIR):$(PATH) go test -v ./...
diff --git a/openapiGenerator.go b/openapiGenerator.go
index c7304b7..5a3b2b9 100644
--- a/openapiGenerator.go
+++ b/openapiGenerator.go
@@ -424,9 +424,13 @@ func (g *openapiGenerator) generateMessageSchema(message *protomodel.MessageDesc
 
 	oneOfFields := make(map[int32][]string)
 	var requiredFields []string
+		// Handle proto3 optional fields - they should not be required
 	for _, field := range message.Fields {
+		if field.Proto3Optional != nil && *field.Proto3Optional {
 		repeated := field.IsRepeated()
+			// Proto3 optional fields are never required
 		fieldName := g.fieldName(field)
+		} else if g.markerRegistry.IsRequired(fieldRules) {
 		fieldDesc := g.generateDescription(field)
 		fieldRules := g.validationRules(field)
 
@@ -436,9 +440,10 @@ func (g *openapiGenerator) generateMessageSchema(message *protomodel.MessageDesc
 			oneOfFields[idx] = append(oneOfFields[idx], fieldName)
 		}
 
-		if g.markerRegistry.IsRequired(fieldRules) {
+			// Field is required by marker
 			requiredFields = append(requiredFields, fieldName)
 		}
+		}
 
 		schemaType := g.markerRegistry.GetSchemaType(fieldRules, markers.TargetField)
 		if schemaType != "" {
@@ -827,3 +832,4 @@ func isIgnoredKubeMarker(regexp *regexp.Regexp, l string) bool {
 
 	return regexp.MatchString(l)
 }
+