diff --git a/doc/changes/12386.md b/doc/changes/12386.md
new file mode 100644
index 00000000000..2c87a3626c8
--- /dev/null
+++ b/doc/changes/12386.md
@@ -0,0 +1 @@
+- Added the ability to scroll horizontally in TUI. (#12386, @Alizter)
diff --git a/src/dune_tui/dune_tui.ml b/src/dune_tui/dune_tui.ml
index 159dad9821e..fa8cd846fdd 100644
--- a/src/dune_tui/dune_tui.ml
+++ b/src/dune_tui/dune_tui.ml
@@ -203,13 +203,7 @@ module Message_viewer = struct
         `Handled
       | _ -> `Unhandled
     in
-    let mouse_handler ~x:_ ~y:_ = function
-      | `Scroll dir ->
-        vscroll ~dir;
-        `Handled
-      | _ -> `Unhandled
-    in
-    ui |> Ui.keyboard_area keyboard_handler |> Ui.mouse_area mouse_handler
+    ui |> Ui.keyboard_area keyboard_handler
   ;;
 end
 
diff --git a/src/dune_tui/widgets/scrollbox.ml b/src/dune_tui/widgets/scrollbox.ml
index 35392cc7cef..bdf9cb044fd 100644
--- a/src/dune_tui/widgets/scrollbox.ml
+++ b/src/dune_tui/widgets/scrollbox.ml
@@ -26,8 +26,8 @@ let scrollbar_wheel_step = 8 (* Wheel event scrolls 1/8th of the screen *)
 let scroll visible offset ~set ~dir =
   let dir =
     match dir with
-    | `Down -> 1
-    | `Up -> -1
+    | `Down | `Right -> 1
+    | `Up | `Left -> -1
   in
   set (offset + (dir * max 1 (visible / scrollbar_wheel_step)))
 ;;
@@ -153,12 +153,14 @@ let make (state_var : State.t Lwd.var) t =
   and+ size = Lwd.get state_var in
   (* Render final box *)
   let box, vscroll, hscroll = compose_bars ui size in
-  let hscroll ~dir =
-    hscroll
-      ~dir:
-        (match dir with
-         | `Right -> `Down
-         | `Left -> `Up)
+  let mouse_handler ~x:_ ~y:_ = function
+    | `Scroll ((`Up | `Down) as dir) ->
+      vscroll ~dir;
+      `Handled
+    | `Scroll ((`Left | `Right) as dir) ->
+      hscroll ~dir;
+      `Handled
+    | _ -> `Unhandled
   in
-  { ui = measure_size box; vscroll; hscroll }
+  { ui = measure_size box |> Ui.mouse_area mouse_handler; vscroll; hscroll }
 ;;
diff --git a/vendor/notty/src/notty.ml b/vendor/notty/src/notty.ml
index 3592bcdf76c..094a16ae59f 100644
--- a/vendor/notty/src/notty.ml
+++ b/vendor/notty/src/notty.ml
@@ -641,7 +641,7 @@ module Unescape = struct
   | `Function of int
   ]
 
-  type button = [ `Left | `Middle | `Right | `Scroll of [ `Up | `Down ] ]
+  type button = [ `Left | `Middle | `Right | `Scroll of [ `Up | `Down | `Left | `Right ] ]
 
   type mods = [ `Meta | `Ctrl | `Shift ] list
 
@@ -725,9 +725,9 @@ module Unescape = struct
       | 0              -> `Left
       | 1 when bit 6 p -> `Scroll `Down
       | 1              -> `Middle
-      | 2 when bit 6 p -> `ALL (* `Scroll `Left *)
+      | 2 when bit 6 p -> `Scroll `Left
       | 2              -> `Right
-      | 3 when bit 6 p -> `ALL (* `Scroll `Right *)
+      | 3 when bit 6 p -> `Scroll `Right
       | _              -> `ALL
     and drag = bit 5 p
     and mods =
diff --git a/vendor/notty/src/notty.mli b/vendor/notty/src/notty.mli
index a3ed5ae139b..7e7eb2bf8d4 100644
--- a/vendor/notty/src/notty.mli
+++ b/vendor/notty/src/notty.mli
@@ -464,7 +464,7 @@ module Unescape : sig
   ]
   (** A selection of extra keys on the keyboard. *)
 
-  type button = [ `Left | `Middle | `Right | `Scroll of [ `Up | `Down ] ]
+  type button = [ `Left | `Middle | `Right | `Scroll of [ `Up | `Down | `Left | `Right ] ]
   (** Mouse buttons. *)
 
   type mods = [ `Meta | `Ctrl | `Shift ] list
@@ -510,7 +510,8 @@ module Unescape : sig
 
          {b Note} Every [`Press (`Left|`Middle|`Right)] generates a corresponding
          [`Release], but there is no portable way to detect which button was
-         released. [`Scroll (`Up|`Down)] presses are not followed by releases.
+         released. [`Scroll (`Up|`Down|`Left|`Right)] presses are not followed
+         by releases.
 
          }
       {- [`Paste (`Start|`End)] are {e bracketed paste} events, signalling the
diff --git a/vendor/update-notty.sh b/vendor/update-notty.sh
index 540774f592f..51ea525b709 100755
--- a/vendor/update-notty.sh
+++ b/vendor/update-notty.sh
@@ -1,6 +1,6 @@
 #!/bin/bash
 
-version=83aad282853bc35564114db72b65a087acf82ccf
+version=54b14f0dc25316a5b64206c55598442ec9d43325
 
 set -e -o pipefail