diff --git a/test/api/v3/unit/models/group.test.js b/test/api/v3/unit/models/group.test.js
index c3c7f615c1..b63e8ca06c 100644
--- a/test/api/v3/unit/models/group.test.js
+++ b/test/api/v3/unit/models/group.test.js
@@ -434,6 +434,47 @@ describe('Group Model', () => {
       });
     });
 
+    describe('#leaveGroup', () => {
+      it('removes user from group quest', async () => {
+        party.quest.members = {
+          [participatingMember._id]: true,
+          [questLeader._id]: true,
+          [nonParticipatingMember._id]: false,
+          [undecidedMember._id]: null,
+        };
+        party.memberCount = 4;
+        await party.save();
+
+        await party.leave(participatingMember);
+
+        party = await Group.findOne({_id: party._id});
+        expect(party.quest.members).to.eql({
+          [questLeader._id]: true,
+          [nonParticipatingMember._id]: false,
+          [undecidedMember._id]: null,
+        });
+      });
+
+      it('deletes a private group when the last member leaves', async () => {
+        party.memberCount = 1;
+
+        await party.leave(participatingMember);
+
+        party = await Group.findOne({_id: party._id});
+        expect(party).to.not.exist;
+      });
+
+      it('does not delete a public group when the last member leaves', async () => {
+        party.memberCount = 1;
+        party.privacy = 'public';
+
+        await party.leave(participatingMember);
+
+        party = await Group.findOne({_id: party._id});
+        expect(party).to.exist;
+      });
+    });
+
     describe('#sendChat', () => {
       beforeEach(() => {
         sandbox.spy(User, 'update');
diff --git a/website/server/models/group.js b/website/server/models/group.js
index 0474104fad..16a432e399 100644
--- a/website/server/models/group.js
+++ b/website/server/models/group.js
@@ -701,6 +701,9 @@ schema.statics.tavernBoss = async function tavernBoss (user, progress) {
 
 schema.methods.leave = async function leaveGroup (user, keep = 'keep-all') {
   let group = this;
+  let update = {
+    $inc: {memberCount: -1},
+  };
 
   let challenges = await Challenge.find({
     _id: {$in: user.challenges},
@@ -724,16 +727,14 @@ schema.methods.leave = async function leaveGroup (user, keep = 'keep-all') {
     pusher.trigger(`presence-group-${group._id}`, 'user-left', {
       userId: user._id,
     });
+
+    update.$unset = {[`quest.members.${user._id}`]: 1};
   }
 
   // If user is the last one in group and group is private, delete it
   if (group.memberCount <= 1 && group.privacy === 'private') {
     promises.push(group.remove());
   } else { // otherwise If the leader is leaving (or if the leader previously left, and this wasn't accounted for)
-    let update = {
-      $inc: {memberCount: -1},
-    };
-
     if (group.leader === user._id) {
       let query = group.type === 'party' ? {'party._id': group._id} : {guilds: group._id};
       query._id = {$ne: user._id};