diff --git a/doc_src/interactive.rst b/doc_src/interactive.rst
index cda77a711..3f5d5e2cf 100644
--- a/doc_src/interactive.rst
+++ b/doc_src/interactive.rst
@@ -557,6 +557,10 @@ Visual mode
 
 - :kbd:`~` toggles the case (upper/lower) on the selection, and enters :ref:`command mode <vi-mode-command>`.
 
+- :kbd:`g,u` lowercases the selection, and enters :ref:`command mode <vi-mode-command>`.
+
+- :kbd:`g,U` uppercases the selection, and enters :ref:`command mode <vi-mode-command>`.
+
 - :kbd:`",*,y` copies the selection to the clipboard, and enters :ref:`command mode <vi-mode-command>`.
 
 .. _custom-binds:
diff --git a/share/functions/fish_vi_key_bindings.fish b/share/functions/fish_vi_key_bindings.fish
index 83242aafb..6b8e7026d 100644
--- a/share/functions/fish_vi_key_bindings.fish
+++ b/share/functions/fish_vi_key_bindings.fish
@@ -317,7 +317,8 @@ function fish_vi_key_bindings --description 'vi-like key bindings for fish'
     bind -s --preset -M visual -m default '",*,y' "fish_clipboard_copy; commandline -f end-selection repaint-mode"
     bind -s --preset -M visual -m default '",+,y' "fish_clipboard_copy; commandline -f end-selection repaint-mode"
     bind -s --preset -M visual -m default '~' togglecase-selection end-selection repaint-mode
-    bind -s --preset -M visual -m default g,U togglecase-selection end-selection repaint-mode
+    bind -s --preset -M visual -m default g,u downcase-selection end-selection repaint-mode
+    bind -s --preset -M visual -m default g,U upcase-selection end-selection repaint-mode
 
     bind -s --preset -M visual -m default ctrl-c end-selection repaint-mode
     bind -s --preset -M visual -m default escape end-selection repaint-mode
diff --git a/src/input.rs b/src/input.rs
index bf87aa6f7..ee0e2dac4 100644
--- a/src/input.rs
+++ b/src/input.rs
@@ -144,6 +144,7 @@ const fn make_md(name: &'static wstr, code: ReadlineCmd) -> InputFunctionMetadat
     make_md(L!("delete-char"), ReadlineCmd::DeleteChar),
     make_md(L!("delete-or-exit"), ReadlineCmd::DeleteOrExit),
     make_md(L!("down-line"), ReadlineCmd::DownLine),
+    make_md(L!("downcase-selection"), ReadlineCmd::DowncaseSelection),
     make_md(L!("downcase-word"), ReadlineCmd::DowncaseWord),
     make_md(L!("end-of-buffer"), ReadlineCmd::EndOfBuffer),
     make_md(L!("end-of-history"), ReadlineCmd::EndOfHistory),
@@ -205,6 +206,7 @@ const fn make_md(name: &'static wstr, code: ReadlineCmd) -> InputFunctionMetadat
     make_md(L!("transpose-words"), ReadlineCmd::TransposeWords),
     make_md(L!("undo"), ReadlineCmd::Undo),
     make_md(L!("up-line"), ReadlineCmd::UpLine),
+    make_md(L!("upcase-selection"), ReadlineCmd::UpcaseSelection),
     make_md(L!("upcase-word"), ReadlineCmd::UpcaseWord),
     make_md(L!("yank"), ReadlineCmd::Yank),
     make_md(L!("yank-pop"), ReadlineCmd::YankPop),
diff --git a/src/input_common.rs b/src/input_common.rs
index 9cc69e802..49f00c892 100644
--- a/src/input_common.rs
+++ b/src/input_common.rs
@@ -108,6 +108,8 @@ pub enum ReadlineCmd {
     DowncaseWord,
     CapitalizeWord,
     TogglecaseChar,
+    UpcaseSelection,
+    DowncaseSelection,
     TogglecaseSelection,
     Execute,
     BeginningOfBuffer,
diff --git a/src/reader.rs b/src/reader.rs
index f6201fdb9..0f5dad50a 100644
--- a/src/reader.rs
+++ b/src/reader.rs
@@ -3571,6 +3571,33 @@ fn handle_readline_command(&mut self, c: ReadlineCmd) {
                     self.update_buff_pos(elt, Some(buff_pos));
                 }
             }
+            rl::UpcaseSelection | rl::DowncaseSelection => {
+                let (elt, el) = self.active_edit_line();
+
+                // Check that we have an active selection and get the bounds.
+                if let Some(selection) = self.get_selection() {
+                    let text = &el.text().as_char_slice()[selection.clone()];
+                    let replacement = if c == rl::UpcaseSelection {
+                        WString::from_iter(text.iter().flat_map(|c| c.to_uppercase()))
+                    } else {
+                        WString::from_iter(text.iter().flat_map(|c| c.to_lowercase()))
+                    };
+
+                    let buff_pos = el.position();
+                    self.replace_substring(elt, selection, replacement);
+
+                    // Restore the buffer position since replace_substring moves
+                    // the buffer position ahead of the replaced text.
+                    // Note: This does not take string length changes into account.
+                    // E.g.: When the cursor was at the right of the selection,
+                    // the selection contains 'ẞ', which is uppercased into 'SS',
+                    // the cursor will stay at the same offset, but it will not be on the same
+                    // character as before.
+                    // The position calculations work on codepoints rather than graphemes, which can
+                    // result in additional issues.
+                    self.update_buff_pos(elt, Some(buff_pos));
+                }
+            }
             rl::UpcaseWord | rl::DowncaseWord | rl::CapitalizeWord => {
                 let (elt, el) = self.active_edit_line();
                 // For capitalize_word, whether we've capitalized a character so far.