diff --git a/example/message.proto b/example/message.proto
index e492991..e1c8959 100644
--- a/example/message.proto
+++ b/example/message.proto
@@ -34,6 +34,7 @@ message GetItemsResponse {
     ItemType type = 2 [(google.api.field_behavior) = REQUIRED];
     string name = 3 [(google.api.field_behavior) = REQUIRED];
     google.protobuf.Timestamp created_at = 4 [(google.api.field_behavior) = REQUIRED];
+    repeated NestedItem nested_item = 5;
   }
 
   repeated Item items = 1 [(google.api.field_behavior) = REQUIRED];
diff --git a/example/openapi.yaml b/example/openapi.yaml
index 4ee548e..61ca7b4 100644
--- a/example/openapi.yaml
+++ b/example/openapi.yaml
@@ -173,6 +173,10 @@ components:
         createdAt:
           type: string
           format: date-time
+        nestedItem:
+          type: array
+          items:
+            $ref: '#/components/schemas/GetItemsResponse.NestedItem'
       required:
         - id
         - type
@@ -202,6 +206,8 @@ components:
       enum:
         - ITEM_TYPE_UNSPECIFIED
         - ITEM_TYPE_BASIC
+    NestedEnum:
+      type: object
     NestedEnum.ItemType:
       type: string
       enum:
diff --git a/internal/gen/generator.go b/internal/gen/generator.go
index 45115cf..8488c8c 100644
--- a/internal/gen/generator.go
+++ b/internal/gen/generator.go
@@ -70,6 +70,12 @@ func NewGenerator(files []*protogen.File, opts ...GeneratorOption) (*Generator,
 				}
 			}
 		}
+	}
+
+	for _, f := range files {
+		if !f.Generate {
+			continue
+		}
 
 		for _, m := range f.Messages {
 			name := descriptorName(m.Desc)
@@ -93,9 +99,10 @@ func NewGenerator(files []*protogen.File, opts ...GeneratorOption) (*Generator,
 
 // Generator instance.
 type Generator struct {
-	spec     *ogen.Spec
-	indent   int
-	requests map[string]struct{}
+	spec            *ogen.Spec
+	indent          int
+	requests        map[string]struct{}
+	descriptorNames map[string]struct{}
 }
 
 // YAML returns OpenAPI specification bytes.
@@ -121,6 +128,7 @@ func (g *Generator) init() {
 	g.spec = ogen.NewSpec()
 	g.spec.Init()
 	g.requests = make(map[string]struct{})
+	g.descriptorNames = make(map[string]struct{})
 }
 
 func (g *Generator) mkMethod(rule HTTPRule, m *protogen.Method) (string, *ogen.Operation, error) {
@@ -143,7 +151,7 @@ func (g *Generator) mkMethod(rule HTTPRule, m *protogen.Method) (string, *ogen.O
 
 func (g *Generator) mkInput(rule HTTPRule, m *protogen.Method, op *ogen.Operation) (string, error) {
 	name := descriptorName(m.Input.Desc)
-	g.requests[name] = struct{}{}
+	g.setRequest(name)
 
 	var (
 		fields        = collectFields(m.Input)
@@ -403,8 +411,29 @@ func (g *Generator) hasSchema(s string) bool {
 	return ok
 }
 
-func (g *Generator) hasRequest(r string) bool {
-	_, ok := g.requests[r]
+func (g *Generator) setRequest(s string) {
+	if g.hasRequest(s) {
+		return
+	}
+
+	g.requests[s] = struct{}{}
+}
+
+func (g *Generator) hasRequest(s string) bool {
+	_, ok := g.requests[s]
+	return ok
+}
+
+func (g *Generator) setDescriptorName(s string) {
+	if g.hasDescriptorName(s) {
+		return
+	}
+
+	g.descriptorNames[s] = struct{}{}
+}
+
+func (g *Generator) hasDescriptorName(s string) bool {
+	_, ok := g.descriptorNames[s]
 	return ok
 }
 
diff --git a/internal/gen/schema.go b/internal/gen/schema.go
index 2bb1336..a699e91 100644
--- a/internal/gen/schema.go
+++ b/internal/gen/schema.go
@@ -59,6 +59,15 @@ func (g *Generator) mkSchema(msg *protogen.Message) error {
 		}
 
 		if field.Message != nil {
+			name := descriptorName(field.Desc)
+			if g.hasDescriptorName(name) {
+				s.SetRef(descriptorRef(field.Message.Desc))
+
+				continue
+			}
+
+			g.setDescriptorName(name)
+
 			if err := g.mkSchema(field.Message); err != nil {
 				return err
 			}