diff --git a/src/commands/backup.rs b/src/commands/backup.rs
index 17f900c..d4d3eda 100644
--- a/src/commands/backup.rs
+++ b/src/commands/backup.rs
@@ -46,8 +46,10 @@ pub(super) async fn execute(
     opts: Opts,
     command: String,
 ) -> Result<()> {
-    let mut snap = SnapshotFile::default();
-    snap.command = Some(command);
+    let mut snap = SnapshotFile {
+        command: Some(command),
+        ..Default::default()
+    };
 
     let config: ConfigFile = be.get_file(&Id::default()).await?;
     let be = DryRunBackend::new(be.clone(), opts.dry_run);
@@ -67,9 +69,7 @@ pub(super) async fn execute(
         .ok_or_else(|| anyhow!("non-unicode hostname {:?}", hostname))?
         .to_string();
 
-    for tags in opts.tag {
-        snap.tags.add_all(tags);
-    }
+    snap.set_tags(opts.tag);
 
     let parent = match (opts.force, opts.parent) {
         (true, _) => None,
diff --git a/src/commands/mod.rs b/src/commands/mod.rs
index 46e9418..9866088 100644
--- a/src/commands/mod.rs
+++ b/src/commands/mod.rs
@@ -17,6 +17,7 @@ mod prune;
 mod repoinfo;
 mod restore;
 mod snapshots;
+mod tag;
 
 use helpers::*;
 use vlog::*;
@@ -76,6 +77,9 @@ enum Command {
 
     /// show general information about repository
     Repoinfo(repoinfo::Opts),
+
+    /// change tags of snapshots
+    Tag(tag::Opts),
 }
 
 pub async fn execute() -> Result<()> {
@@ -107,5 +111,6 @@ pub async fn execute() -> Result<()> {
         Command::Prune(opts) => prune::execute(&dbe, opts).await,
         Command::Restore(opts) => restore::execute(&dbe, opts).await,
         Command::Repoinfo(opts) => repoinfo::execute(&dbe, opts).await,
+        Command::Tag(opts) => tag::execute(&dbe, opts).await,
     }
 }
diff --git a/src/commands/tag.rs b/src/commands/tag.rs
new file mode 100644
index 0000000..5fd084e
--- /dev/null
+++ b/src/commands/tag.rs
@@ -0,0 +1,63 @@
+use anyhow::Result;
+use clap::Parser;
+
+use crate::backend::{DecryptFullBackend, FileType};
+use crate::repo::{SnapshotFile, SnapshotFilter, StringList};
+
+#[derive(Parser)]
+pub(super) struct Opts {
+    #[clap(flatten)]
+    filter: SnapshotFilter,
+
+    /// Tags to add add (can be specified multiple times)
+    #[clap(long, value_name = "TAG[,TAG,..]", conflicts_with = "remove")]
+    add: Vec<StringList>,
+
+    /// Tags to remove (can be specified multiple times)
+    #[clap(long, value_name = "TAG[,TAG,..]")]
+    remove: Vec<StringList>,
+
+    /// Tag list to set (can be specified multiple times)
+    #[clap(long, value_name = "TAG[,TAG,..]", conflicts_with = "remove")]
+    set: Vec<StringList>,
+    // TODO: allow giving specific snapshots
+}
+
+pub(super) async fn execute(be: &impl DecryptFullBackend, opts: Opts) -> Result<()> {
+    let snapshots = SnapshotFile::all_from_backend(be).await?;
+
+    let mut count = 0;
+    for sn in snapshots.into_iter().filter(|sn| sn.matches(&opts.filter)) {
+        if modify_sn(sn, be, &opts).await? {
+            count += 1;
+        }
+    }
+
+    println!("changed {} snapshot(s)", count);
+
+    Ok(())
+}
+
+async fn modify_sn(
+    mut sn: SnapshotFile,
+    be: &impl DecryptFullBackend,
+    opts: &Opts,
+) -> Result<bool> {
+    let mut changed = false;
+
+    if !opts.set.is_empty() {
+        changed |= sn.set_tags(opts.set.clone());
+    }
+    changed |= sn.add_tags(opts.add.clone());
+    changed |= sn.remove_tags(opts.remove.clone());
+
+    // FIXME: For some reason, changed is always true...?!?
+    if changed {
+        // TODO: Save original snapshot ID
+        // TODO: Save and delete in parallel
+        be.save_file(&sn).await?;
+        be.remove(FileType::Snapshot, &sn.id).await?;
+    }
+
+    Ok(changed)
+}
diff --git a/src/repo/snapshotfile.rs b/src/repo/snapshotfile.rs
index 5f832c0..15159a8 100644
--- a/src/repo/snapshotfile.rs
+++ b/src/repo/snapshotfile.rs
@@ -184,6 +184,32 @@ impl SnapshotFile {
             && self.tags.matches(&filter.tags)
             && (filter.hostnames.is_empty() || filter.hostnames.contains(&self.hostname))
     }
+
+    /// Add tag lists to snapshot. return wheter snapshot was changed
+    pub fn add_tags(&mut self, tag_lists: Vec<StringList>) -> bool {
+        let old_tags = self.tags.clone();
+        self.tags.add_all(tag_lists);
+        self.tags.sort();
+
+        old_tags == self.tags
+    }
+
+    /// Set tag lists to snapshot. return wheter snapshot was changed
+    pub fn set_tags(&mut self, tag_lists: Vec<StringList>) -> bool {
+        let old_tags = std::mem::take(&mut self.tags);
+        self.tags.add_all(tag_lists);
+        self.tags.sort();
+
+        old_tags == self.tags
+    }
+
+    /// Remove tag lists from snapshot. return wheter snapshot was changed
+    pub fn remove_tags(&mut self, tag_lists: Vec<StringList>) -> bool {
+        let old_tags = self.tags.clone();
+        self.tags.remove_all(tag_lists);
+
+        old_tags == self.tags
+    }
 }
 
 impl PartialOrd for SnapshotFile {
@@ -197,7 +223,7 @@ impl Ord for SnapshotFile {
     }
 }
 
-#[derive(Default, Debug, PartialEq, Eq, PartialOrd, Serialize, Deserialize)]
+#[derive(Default, Debug, PartialEq, Eq, PartialOrd, Clone, Serialize, Deserialize)]
 pub struct StringList(Vec<String>);
 
 impl FromStr for StringList {
@@ -226,12 +252,27 @@ impl StringList {
         }
     }
 
-    pub fn add_all(&mut self, sl: StringList) {
+    pub fn add_list(&mut self, sl: StringList) {
         for s in sl.0 {
             self.add(s)
         }
     }
 
+    pub fn add_all(&mut self, string_lists: Vec<StringList>) {
+        for sl in string_lists {
+            self.add_list(sl)
+        }
+    }
+
+    pub fn remove_all(&mut self, string_lists: Vec<StringList>) {
+        self.0
+            .retain(|s| !string_lists.iter().any(|sl| sl.contains(s)));
+    }
+
+    pub fn sort(&mut self) {
+        self.0.sort_unstable();
+    }
+
     pub fn formatln(&self) -> String {
         self.0
             .iter()