diff --git a/CHANGELOG.md b/CHANGELOG.md
index 350c62d..4ba376b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -26,6 +26,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Fixed watch IMAP envelopes when folder was empty [#179].
 - Prevented parsing of undefined config options [#188].
+- Fixed `In-Reply-To` header being skipped from mailto URLs [#194].
 
 ## [1.0.0-beta.3] - 2024-02-25
 
@@ -814,3 +815,4 @@ Few major concepts changed:
 [#173]: https://todo.sr.ht/~soywod/pimalaya/173
 [#184]: https://todo.sr.ht/~soywod/pimalaya/184
 [#188]: https://todo.sr.ht/~soywod/pimalaya/188
+[#194]: https://todo.sr.ht/~soywod/pimalaya/194
diff --git a/src/email/message/command/mailto.rs b/src/email/message/command/mailto.rs
index e855a73..540aa2f 100644
--- a/src/email/message/command/mailto.rs
+++ b/src/email/message/command/mailto.rs
@@ -69,11 +69,22 @@ impl MessageMailtoCommand {
         let mut body = String::new();
 
         for (key, val) in self.url.query_pairs() {
-            match key.to_lowercase().as_bytes() {
-                b"cc" => builder = builder.cc(val.to_string()),
-                b"bcc" => builder = builder.bcc(val.to_string()),
-                b"subject" => builder = builder.subject(val),
-                b"body" => body += &val,
+            match key {
+                key if key.eq_ignore_ascii_case("in-reply-to") => {
+                    builder = builder.in_reply_to(val.to_string());
+                }
+                key if key.eq_ignore_ascii_case("cc") => {
+                    builder = builder.cc(val.to_string());
+                }
+                key if key.eq_ignore_ascii_case("bcc") => {
+                    builder = builder.bcc(val.to_string());
+                }
+                key if key.eq_ignore_ascii_case("subject") => {
+                    builder = builder.subject(val.to_string());
+                }
+                key if key.eq_ignore_ascii_case("body") => {
+                    body += &val;
+                }
                 _ => (),
             }
         }