diff --git a/lib/document.js b/lib/document.js
index db5347f4efd..ad216686859 100644
--- a/lib/document.js
+++ b/lib/document.js
@@ -3464,9 +3464,9 @@ Document.prototype.$toObject = function(options, json) {
 
   const path = json ? 'toJSON' : 'toObject';
   const baseOptions = this.constructor &&
-  this.constructor.base &&
-  this.constructor.base.options &&
-  get(this.constructor.base.options, path) || {};
+    this.constructor.base &&
+    this.constructor.base.options &&
+    get(this.constructor.base.options, path) || {};
   const schemaOptions = this.$__schema && this.$__schema.options || {};
   // merge base default options with Schema's set default options if available.
   // `clone` is necessary here because `utils.options` directly modifies the second input.
@@ -3503,7 +3503,8 @@ Document.prototype.$toObject = function(options, json) {
     _isNested: true,
     json: json,
     minimize: _minimize,
-    flattenMaps: flattenMaps
+    flattenMaps: flattenMaps,
+    _seen: (options && options._seen) || new Map()
   });
 
   if (utils.hasUserDefinedProperty(options, 'getters')) {
diff --git a/lib/helpers/clone.js b/lib/helpers/clone.js
index 7e0fd97f9eb..6936fa642fc 100644
--- a/lib/helpers/clone.js
+++ b/lib/helpers/clone.js
@@ -119,9 +119,15 @@ module.exports = clone;
 function cloneObject(obj, options, isArrayChild) {
   const minimize = options && options.minimize;
   const omitUndefined = options && options.omitUndefined;
+  const seen = options && options._seen;
   const ret = {};
   let hasKeys;
 
+  if (seen && seen.has(obj)) {
+    return seen.get(obj);
+  } else if (seen) {
+    seen.set(obj, ret);
+  }
   if (trustedSymbol in obj) {
     ret[trustedSymbol] = obj[trustedSymbol];
   }
diff --git a/test/document.test.js b/test/document.test.js
index 1f3d35decc3..0950dd4fc6a 100644
--- a/test/document.test.js
+++ b/test/document.test.js
@@ -1035,6 +1035,25 @@ describe('document', function() {
       assert.ok(posts[0].postedBy._id);
     });
 
+    it('handles infinite recursion (gh-11756)', function() {
+      const User = db.model('User', Schema({
+        name: { type: String, required: true },
+        posts: [{ type: mongoose.Types.ObjectId, ref: 'Post' }]
+      }));
+
+      const Post = db.model('Post', Schema({
+        creator: { type: Schema.Types.ObjectId, ref: 'User' }
+      }));
+
+      const user = new User({ name: 'Test', posts: [] });
+      const post = new Post({ creator: user });
+      user.posts.push(post);
+
+      const inspected = post.inspect();
+      assert.ok(inspected);
+      assert.equal(inspected.creator.posts[0].creator.name, 'Test');
+    });
+
     it('populate on nested path (gh-5703)', function() {
       const toySchema = new mongoose.Schema({ color: String });
       const Toy = db.model('Cat', toySchema);