diff --git a/crates/apub/src/activities/comment/create_or_update.rs b/crates/apub/src/activities/comment/create_or_update.rs
index eab2a5771..ab59eb703 100644
--- a/crates/apub/src/activities/comment/create_or_update.rs
+++ b/crates/apub/src/activities/comment/create_or_update.rs
@@ -50,7 +50,7 @@ impl CreateOrUpdateComment {
     )?;
     let maa = collect_non_local_mentions(&comment, &community, context).await?;
 
-    let create_or_update = CreateOrUpdateComment {
+    let mut create_or_update = CreateOrUpdateComment {
       actor: ObjectId::new(actor.actor_id()),
       to: vec![public()],
       object: comment.into_apub(context).await?,
@@ -61,6 +61,11 @@ impl CreateOrUpdateComment {
       unparsed: Default::default(),
     };
 
+    // To make mention notifications work on Mastodon/Pleroma, it is necessary that tag and cc
+    // are set on both the activity and the object.
+    create_or_update.object.tag = Some(create_or_update.tag.clone());
+    create_or_update.object.cc = create_or_update.cc.clone();
+
     let activity = AnnouncableActivities::CreateOrUpdateComment(create_or_update);
     send_activity_in_community(activity, &id, actor, &community, maa.inboxes, context).await
   }
diff --git a/crates/apub/src/activities/comment/mod.rs b/crates/apub/src/activities/comment/mod.rs
index d104db2fe..f0468f970 100644
--- a/crates/apub/src/activities/comment/mod.rs
+++ b/crates/apub/src/activities/comment/mod.rs
@@ -26,6 +26,7 @@ use crate::{
   fetcher::webfinger::WebfingerResponse,
   objects::{comment::ApubComment, community::ApubCommunity, person::ApubPerson},
 };
+use lemmy_utils::settings::structs::Settings;
 
 pub mod create_or_update;
 
@@ -68,7 +69,15 @@ pub async fn collect_non_local_mentions(
   let mut inboxes = vec![parent_creator.shared_inbox_or_inbox_url()];
 
   // Add the mention tag
-  let mut tags = Vec::new();
+  let mut parent_creator_tag = Mention::new();
+  parent_creator_tag
+    .set_href(parent_creator.actor_id.clone().into())
+    .set_name(format!(
+      "@{}@{}",
+      &parent_creator.name,
+      &Settings::get().hostname
+    ));
+  let mut tags = vec![parent_creator_tag];
 
   // Get the person IDs for any mentions
   let mentions = scrape_text_for_mentions(&comment.content)
diff --git a/crates/apub/src/objects/comment.rs b/crates/apub/src/objects/comment.rs
index 83895e8d3..b3f520dae 100644
--- a/crates/apub/src/objects/comment.rs
+++ b/crates/apub/src/objects/comment.rs
@@ -117,6 +117,7 @@ impl ApubObject for ApubComment {
       in_reply_to,
       published: Some(convert_datetime(self.published)),
       updated: self.updated.map(convert_datetime),
+      tag: None,
       unparsed: Default::default(),
     };
 
diff --git a/crates/apub/src/protocol/objects/note.rs b/crates/apub/src/protocol/objects/note.rs
index 784e6f9f8..5bcd1a553 100644
--- a/crates/apub/src/protocol/objects/note.rs
+++ b/crates/apub/src/protocol/objects/note.rs
@@ -3,7 +3,7 @@ use crate::{
   objects::{comment::ApubComment, person::ApubPerson, post::ApubPost},
   protocol::Source,
 };
-use activitystreams::{object::kind::NoteType, unparsed::Unparsed};
+use activitystreams::{link::Mention, object::kind::NoteType, unparsed::Unparsed};
 use anyhow::anyhow;
 use chrono::{DateTime, FixedOffset};
 use lemmy_api_common::blocking;
@@ -38,6 +38,7 @@ pub struct Note {
   pub(crate) in_reply_to: ObjectId<PostOrComment>,
   pub(crate) published: Option<DateTime<FixedOffset>>,
   pub(crate) updated: Option<DateTime<FixedOffset>>,
+  pub(crate) tag: Option<Vec<Mention>>,
   #[serde(flatten)]
   pub(crate) unparsed: Unparsed,
 }