diff --git a/app/activitypub/routes.py b/app/activitypub/routes.py
index fa3dd3fe..dc86eeca 100644
--- a/app/activitypub/routes.py
+++ b/app/activitypub/routes.py
@@ -25,7 +25,7 @@ from app.activitypub.util import public_key, users_total, active_half_year, acti
     update_post_from_activity, undo_vote, undo_downvote, post_to_page, get_redis_connection, find_reported_object, \
     process_report, ensure_domains_match, can_edit, can_delete, remove_data_from_banned_user, resolve_remote_post, \
     inform_followers_of_post_update, comment_model_to_json, restore_post_or_comment, ban_local_user, unban_local_user, \
-    lock_post, log_incoming_ap, find_community_ap_id
+    lock_post, log_incoming_ap, find_community_ap_id, site_ban_remove_data
 from app.utils import gibberish, get_setting, render_template, \
     community_membership, ap_datetime, ip_address, can_downvote, \
     can_upvote, can_create_post, awaken_dormant_instance, shorten_string, can_create_post_reply, sha256_digest, \
@@ -759,6 +759,36 @@ def process_inbox_request(request_json, store_ap_json):
                 log_incoming_ap(request_json['id'], APLOG_REPORT, APLOG_IGNORED, request_json if store_ap_json else None, 'Report ignored due to missing content')
             return
 
+        if request_json['type'] == 'Block':     # remote site is banning one of their users
+            blocker = user
+            blocked_ap_id = request_json['object'].lower()
+            blocked = User.query.filter_by(ap_profile_id=blocked_ap_id).first()
+            if store_ap_json:
+                request_json['cc'] = []                                         # cut very long list of instances
+            if not blocked:
+                log_incoming_ap(request_json['id'], APLOG_USERBAN, APLOG_IGNORED, request_json if store_ap_json else None, 'Does not exist here')
+                return
+            block_from_ap_id = request_json['target']
+            remove_data = request_json['removeData'] if 'removeData' in request_json else False
+
+            # Lemmy currently only sends userbans for admins banning local users
+            # Banning remote users is hacked by banning them from every community of which they are a part
+            # There's plans to change this in the future though.
+            if not blocker.is_instance_admin() and not blocked.instance_id == blocker.instance_id:
+                log_incoming_ap(request_json['id'], APLOG_USERBAN, APLOG_FAILURE, request_json if store_ap_json else None, 'Does not have permission')
+                return
+
+            # request_json includes 'expires' and 'endTime' (same thing) but nowhere to record this and check in future for end in ban.
+
+            if remove_data == True:
+                site_ban_remove_data(blocker.id, blocked)
+                log_incoming_ap(request_json['id'], APLOG_USERBAN, APLOG_SUCCESS, request_json if store_ap_json else None)
+            else:
+                #blocked.banned = True         # uncommented until there's a mechanism for processing ban expiry date
+                #db.session.commit()
+                log_incoming_ap(request_json['id'], APLOG_USERBAN, APLOG_IGNORED, request_json if store_ap_json else None, 'Banned, but content retained')
+            return
+
 
         # -- below this point is code that will be incrementally replaced to use log_incoming_ap() instead --
 
diff --git a/app/activitypub/util.py b/app/activitypub/util.py
index a2669911..430f3e0f 100644
--- a/app/activitypub/util.py
+++ b/app/activitypub/util.py
@@ -1429,6 +1429,48 @@ def restore_post_or_comment(object_json, aplog_id):
             aplog.exception_message = 'Unable to resolve restorer or target'
 
 
+def site_ban_remove_data(blocker_id, blocked):
+    replies = PostReply.query.filter_by(user_id=blocked.id, deleted=False)
+    for reply in replies:
+        reply.deleted = True
+        reply.deleted_by = blocker_id
+        if not blocked.bot:
+            reply.post.reply_count -= 1
+        reply.community.post_reply_count -= 1
+    blocked.reply_count = 0
+    db.session.commit()
+
+    posts = Post.query.filter_by(user_id=blocked.id, deleted=False)
+    for post in posts:
+        post.deleted = True
+        post.deleted_by = blocker_id
+        post.community.post_count -= 1
+        if post.url and post.cross_posts is not None:
+            old_cross_posts = Post.query.filter(Post.id.in_(post.cross_posts)).all()
+            post.cross_posts.clear()
+            for ocp in old_cross_posts:
+                if ocp.cross_posts is not None and post.id in ocp.cross_posts:
+                    ocp.cross_posts.remove(post.id)
+    blocked.post_count = 0
+    db.session.commit()
+
+    # Delete all their images to save moderators from having to see disgusting stuff.
+    # Images attached to posts can't be restored, but site ban reversals don't have a 'removeData' field anyway.
+    files = File.query.join(Post).filter(Post.user_id == blocked.id).all()
+    for file in files:
+        file.delete_from_disk()
+        file.source_url = ''
+    if blocked.avatar_id:
+        blocked.avatar.delete_from_disk()
+        blocked.avatar.source_url = ''
+    if blocked.cover_id:
+        blocked.cover.delete_from_disk()
+        blocked.cover.source_url = ''
+    # blocked.banned = True                     # uncommented until there's a mechanism for processing ban expiry date
+
+    db.session.commit()
+
+
 def remove_data_from_banned_user(deletor_ap_id, user_ap_id, target):
     if current_app.debug:
         remove_data_from_banned_user_task(deletor_ap_id, user_ap_id, target)