diff --git a/crates/ely_app/src/shell/chrome/sidebar.rs b/crates/ely_app/src/shell/chrome/sidebar.rs
index e40d3ab..e466a22 100644
--- a/crates/ely_app/src/shell/chrome/sidebar.rs
+++ b/crates/ely_app/src/shell/chrome/sidebar.rs
@@ -2,9 +2,9 @@ use ely_browser_core::BrowserSnapshot;
 use ely_design_system::{colors, spacing};
 use ely_domain::BrowserTab;
 use gpui::{
-    AnyElement, BoxShadow, Context, InteractiveElement, IntoElement, ParentElement, SharedString,
-    StatefulInteractiveElement, Styled, div, hsla, linear_color_stop, linear_gradient, point,
-    prelude::FluentBuilder, px, rgb, rgba,
+    AnyElement, BoxShadow, Context, InteractiveElement, IntoElement, MouseButton,
+    ParentElement, SharedString, StatefulInteractiveElement, Styled, div, hsla,
+    linear_color_stop, linear_gradient, point, prelude::FluentBuilder, px, rgb, rgba,
 };
 use gpui_component::{IconName, StyledExt, scroll::ScrollableElement};
 
@@ -22,6 +22,7 @@ impl ElyShell {
         div()
             .w(px(sidebar_width))
             .h_full()
+            .relative()
             .flex()
             .flex_col()
             .rounded(px(spacing::RADIUS_CARD))
@@ -60,6 +61,7 @@ impl ElyShell {
                     .child(self.render_new_tab_row(cx)),
             )
             .child(self.render_sidebar_footer(snapshot, cx))
+            .child(render_sidebar_resize_handle(cx))
             .into_any_element()
     }
 
@@ -419,6 +421,31 @@ const UNREAD_BADGE_BG: u32 = 0x281e140f;
 /// never participates in hit testing.
 const HIGHLIGHT_BORDER: u32 = 0xffffff80;
 
+/// Sidebar resize affordance pinned to the panel's right edge. The
+/// strip itself is invisible until hovered; on mouse-down it tells the
+/// shell to capture the drag origin so window-level mouse-move can
+/// compute the live width.
+fn render_sidebar_resize_handle(cx: &mut Context<ElyShell>) -> AnyElement {
+    div()
+        .id(SharedString::from("sidebar-resize-handle"))
+        .absolute()
+        .top_0()
+        .bottom_0()
+        .right(px(-2.0))
+        .w(px(6.0))
+        .cursor_col_resize()
+        .hover(|style| style.bg(rgba(RESIZE_HANDLE_HOVER_BG)))
+        .on_mouse_down(
+            MouseButton::Left,
+            cx.listener(|shell, event: &gpui::MouseDownEvent, _, cx| {
+                shell.begin_sidebar_resize(f32::from(event.position.x), cx);
+            }),
+        )
+        .into_any_element()
+}
+
+const RESIZE_HANDLE_HOVER_BG: u32 = 0xffffff66;
+
 /// Maps appearance translucency_pct to a panel rgba u32 tinted by the
 /// active wallpaper theme.
 ///
diff --git a/crates/ely_app/src/shell/mod.rs b/crates/ely_app/src/shell/mod.rs
index 5c06b4e..58c960c 100644
--- a/crates/ely_app/src/shell/mod.rs
+++ b/crates/ely_app/src/shell/mod.rs
@@ -68,6 +68,10 @@ pub struct ElyShell {
     pub(crate) workspace_picker_open: bool,
     pub(crate) sidebar_hover_expanded: bool,
     pub(crate) command_selected_index: usize,
+    /// Live state for sidebar-resize drag. While the user holds the
+    /// resize handle: `(mouse_x_at_drag_start, sidebar_width_px_at_drag_start)`.
+    /// `None` whenever no drag is in flight.
+    pub(crate) sidebar_resize_origin: Option<(f32, u16)>,
     download_action_error: Option<String>,
     download_clear_confirmation: bool,
     download_security_confirmation: Option<PendingDownloadFileAction>,
@@ -182,6 +186,7 @@ impl ElyShell {
             workspace_picker_open: false,
             sidebar_hover_expanded: false,
             command_selected_index: 0,
+            sidebar_resize_origin: None,
             download_action_error: None,
             download_clear_confirmation: false,
             download_security_confirmation: None,
diff --git a/crates/ely_app/src/shell/render.rs b/crates/ely_app/src/shell/render.rs
index 64e5505..3703113 100644
--- a/crates/ely_app/src/shell/render.rs
+++ b/crates/ely_app/src/shell/render.rs
@@ -2,9 +2,9 @@ use ely_browser_core::BrowserSnapshot;
 use ely_design_system::{colors, spacing};
 use ely_domain::{BrowserTab, DEFAULT_SIDEBAR_WIDTH_PX, HIDDEN_SIDEBAR_WIDTH_PX};
 use gpui::{
-    AnyElement, Context, InteractiveElement, IntoElement, KeyDownEvent, MouseMoveEvent,
-    ParentElement, Render, SharedString, StatefulInteractiveElement, Styled, Window, div,
-    prelude::FluentBuilder, px, rgb, rgba,
+    AnyElement, Context, InteractiveElement, IntoElement, KeyDownEvent, MouseButton,
+    MouseMoveEvent, MouseUpEvent, ParentElement, Render, SharedString,
+    StatefulInteractiveElement, Styled, Window, div, prelude::FluentBuilder, px, rgb, rgba,
 };
 
 use super::chrome::command_match::visible_command_rows;
@@ -68,6 +68,7 @@ impl ElyShell {
             .on_action(cx.listener(Self::on_zoom_in))
             .on_action(cx.listener(Self::on_zoom_out))
             .on_mouse_move(cx.listener(Self::on_window_mouse_move))
+            .on_mouse_up(MouseButton::Left, cx.listener(Self::on_window_mouse_up))
             .capture_key_down(cx.listener(Self::on_command_overlay_key_down))
             .font_family(SANS_FAMILY)
             .text_color(rgb(colors::INK))
@@ -214,6 +215,15 @@ impl ElyShell {
     ) {
         let cursor_x = f32::from(event.position.x);
 
+        if let Some((origin_x, origin_width)) = self.sidebar_resize_origin {
+            let delta = cursor_x - origin_x;
+            let candidate = (f32::from(origin_width) + delta)
+                .clamp(MIN_RESIZE_WIDTH_PX, MAX_RESIZE_WIDTH_PX)
+                .round() as u16;
+            self.set_active_sidebar_width(candidate, cx);
+            return;
+        }
+
         if cursor_x >= REVEAL_THRESHOLD_PX && cursor_x <= COLLAPSE_THRESHOLD_PX {
             return;
         }
@@ -235,6 +245,36 @@ impl ElyShell {
         }
     }
 
+    pub(super) fn begin_sidebar_resize(
+        &mut self,
+        cursor_x: f32,
+        cx: &mut Context<Self>,
+    ) {
+        let ShellState::Ready(core) = &self.state else {
+            return;
+        };
+        let Some(width) = core.active_space_sidebar_width() else {
+            return;
+        };
+        self.sidebar_resize_origin = Some((cursor_x, width));
+        cx.notify();
+    }
+
+    pub(super) fn end_sidebar_resize(&mut self, cx: &mut Context<Self>) {
+        if self.sidebar_resize_origin.take().is_some() {
+            cx.notify();
+        }
+    }
+
+    fn on_window_mouse_up(
+        &mut self,
+        _event: &MouseUpEvent,
+        _window: &mut Window,
+        cx: &mut Context<Self>,
+    ) {
+        self.end_sidebar_resize(cx);
+    }
+
     fn render_hidden_sidebar_rail(&mut self, cx: &mut Context<Self>) -> AnyElement {
         div()
             .id(SharedString::from("hidden-sidebar-rail"))
@@ -256,6 +296,16 @@ impl ElyShell {
 /// never participates in hit testing.
 const MAIN_PANE_HIGHLIGHT_BORDER: u32 = 0xffffff80;
 
+/// Lower clamp for the live sidebar-resize drag. Stays a touch above
+/// the per-space DEFAULT so a casual flick doesn't snap the user to a
+/// nearly-collapsed pane that's awkward to recover from. The toggle
+/// button still owns the discrete collapse-to-rail behavior.
+pub(super) const MIN_RESIZE_WIDTH_PX: f32 = 220.0;
+
+/// Upper clamp — wider than this and the main pane disappears on
+/// smaller windows. Tuned to fit comfortably on a 1280-wide window.
+pub(super) const MAX_RESIZE_WIDTH_PX: f32 = 480.0;
+
 /// Cursor x within this px from the left edge auto-reveals the hidden sidebar.
 /// Sized so the user only triggers the reveal when they actually approach the
 /// rail, not when they hover the page content.