diff --git a/CHANGELOG.md b/CHANGELOG.md
index db8fbe0f..a537eda5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -90,6 +90,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Fixed pre-release archives issue. [#492]
 - Fixed mailto parsing issue. [core#10]
+- Fixed `Answered` flag not set when replying to a message. [#508]
 
 ## [1.0.0-beta.4] - 2024-04-16
 
@@ -897,4 +898,5 @@ Few major concepts changed:
 
 [#492]: https://github.com/pimalaya/himalaya/issues/492
 [#496]: https://github.com/pimalaya/himalaya/issues/496
+[#508]: https://github.com/pimalaya/himalaya/issues/508
 [core#10]: https://github.com/pimalaya/core/issues/10
diff --git a/src/email/message/command/reply.rs b/src/email/message/command/reply.rs
index 7bc1d2df..4dd1b2cd 100644
--- a/src/email/message/command/reply.rs
+++ b/src/email/message/command/reply.rs
@@ -2,7 +2,7 @@ use std::sync::Arc;
 
 use clap::Parser;
 use color_eyre::{eyre::eyre, Result};
-use email::{backend::feature::BackendFeatureSource, config::Config};
+use email::{backend::feature::BackendFeatureSource, config::Config, flag::Flag};
 use pimalaya_tui::{
     himalaya::{backend::BackendBuilder, editor},
     terminal::{cli::printer::Printer, config::TomlConfig as _},
@@ -82,6 +82,11 @@ impl MessageReplyCommand {
             .with_reply_all(self.reply.all)
             .build()
             .await?;
-        editor::edit_tpl_with_editor(account_config, printer, &backend, tpl).await
+
+        editor::edit_tpl_with_editor(account_config, printer, &backend, tpl).await?;
+
+        backend.add_flag(folder, &[id], Flag::Answered).await?;
+
+        Ok(())
     }
 }