diff --git a/rslib/src/storage/note/mod.rs b/rslib/src/storage/note/mod.rs
index b9798f26f..03c82e919 100644
--- a/rslib/src/storage/note/mod.rs
+++ b/rslib/src/storage/note/mod.rs
@@ -6,10 +6,12 @@ use std::collections::HashSet;
 
 use rusqlite::params;
 use rusqlite::Row;
+use unicase::UniCase;
 
 use crate::import_export::package::NoteMeta;
 use crate::notes::NoteTags;
 use crate::prelude::*;
+use crate::tags::immediate_parent_name_unicase;
 use crate::tags::join_tags;
 use crate::tags::split_tags;
 
@@ -217,16 +219,20 @@ impl super::SqliteStorage {
             .map_err(Into::into)
     }
 
-    pub(crate) fn all_tags_in_notes(&self) -> Result<HashSet<String>> {
+    /// All tags referenced by notes, and any parent tags as well.
+    pub(crate) fn all_tags_in_notes(&self) -> Result<HashSet<UniCase<String>>> {
         let mut stmt = self
             .db
             .prepare_cached("select tags from notes where tags != ''")?;
         let mut query = stmt.query([])?;
-        let mut seen: HashSet<String> = HashSet::new();
+        let mut seen: HashSet<UniCase<String>> = HashSet::new();
         while let Some(rows) = query.next()? {
             for tag in split_tags(rows.get_ref_unwrap(0).as_str()?) {
-                if !seen.contains(tag) {
-                    seen.insert(tag.to_string());
+                seen.insert(UniCase::new(tag.to_string()));
+                let mut tag_unicase = UniCase::new(tag);
+                while let Some(parent_name) = immediate_parent_name_unicase(tag_unicase) {
+                    seen.insert(UniCase::new(parent_name.to_string()));
+                    tag_unicase = UniCase::new(&parent_name);
                 }
             }
         }
diff --git a/rslib/src/tags/mod.rs b/rslib/src/tags/mod.rs
index c05dacab5..aab335a3d 100644
--- a/rslib/src/tags/mod.rs
+++ b/rslib/src/tags/mod.rs
@@ -55,7 +55,7 @@ fn is_tag_separator(c: char) -> bool {
     c == ' ' || c == '\u{3000}'
 }
 
-fn immediate_parent_name_unicase(tag_name: UniCase<&str>) -> Option<UniCase<&str>> {
+pub(crate) fn immediate_parent_name_unicase(tag_name: UniCase<&str>) -> Option<UniCase<&str>> {
     tag_name.rsplit_once('\x1f').map(|t| t.0).map(UniCase::new)
 }
 
diff --git a/rslib/src/tags/remove.rs b/rslib/src/tags/remove.rs
index 15606db1d..187b38669 100644
--- a/rslib/src/tags/remove.rs
+++ b/rslib/src/tags/remove.rs
@@ -1,6 +1,8 @@
 // Copyright: Ankitects Pty Ltd and contributors
 // License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
 
+use unicase::UniCase;
+
 use super::matcher::TagMatcher;
 use crate::prelude::*;
 
@@ -84,7 +86,7 @@ impl Collection {
             .storage
             .all_tags()?
             .into_iter()
-            .filter(|tag| !in_notes.contains(&tag.name));
+            .filter(|tag| !in_notes.contains(&UniCase::new(tag.name.clone())));
         for tag in need_remove {
             self.remove_single_tag_undoable(tag)?;
             count += 1;