diff --git a/resources/lang/en.json b/resources/lang/en.json
index b1c181b7a8..d77da2867b 100644
--- a/resources/lang/en.json
+++ b/resources/lang/en.json
@@ -683,6 +683,10 @@
     "lobby_id_visibility_label": "Hidden Lobby IDs",
     "lobby_id_visibility_desc": "Hide Lobby ID in private lobby creation",
     "toggle_visibility": "Toggle Visibility",
+    "hold_middle_click_label": "Hold Middle-Click to Upgrade",
+    "hold_middle_click_desc": "Hold the middle mouse button to continuously upgrade a building.",
+    "hold_middle_click_speed_label": "Upgrade Hold Speed",
+    "hold_middle_click_speed_desc": "How fast buildings upgrade while holding middle-click. Lower = faster. (50–500ms)",
     "left_click_label": "Left Click to Open Menu",
     "left_click_desc": "When ON, left-click opens menu and sword button attacks. When OFF, left-click attacks directly.",
     "left_click_menu": "Left Click Menu",
diff --git a/src/client/InputHandler.ts b/src/client/InputHandler.ts
index 1c12cf61b3..45e6be35be 100644
--- a/src/client/InputHandler.ts
+++ b/src/client/InputHandler.ts
@@ -230,6 +230,11 @@ export class InputHandler {
 
   private readonly userSettings: UserSettings = new UserSettings();
 
+  private holdUpgradeInterval: ReturnType<typeof setInterval> | undefined =
+    undefined;
+  private holdUpgradeTimeout: ReturnType<typeof setTimeout> | undefined =
+    undefined;
+
   constructor(
     private gameView: GameView,
     public uiState: UIState,
@@ -581,6 +586,16 @@ export class InputHandler {
     if (event.button === 1) {
       event.preventDefault();
       this.eventBus.emit(new AutoUpgradeEvent(event.clientX, event.clientY));
+
+      if (this.userSettings.holdMiddleClickUpgrade()) {
+        this.holdUpgradeTimeout = setTimeout(() => {
+          this.holdUpgradeInterval = setInterval(() => {
+            this.eventBus.emit(
+              new AutoUpgradeEvent(event.clientX, event.clientY),
+            );
+          }, this.userSettings.holdMiddleClickUpgradeSpeed());
+        }, 400);
+      }
       return;
     }
 
@@ -637,6 +652,10 @@ export class InputHandler {
   onPointerUp(event: PointerEvent) {
     if (event.button === 1) {
       event.preventDefault();
+      clearTimeout(this.holdUpgradeTimeout);
+      clearInterval(this.holdUpgradeInterval);
+      this.holdUpgradeTimeout = undefined;
+      this.holdUpgradeInterval = undefined;
       return;
     }
 
diff --git a/src/client/UserSettingModal.ts b/src/client/UserSettingModal.ts
index 1d599ad0dd..ce7dcdb00f 100644
--- a/src/client/UserSettingModal.ts
+++ b/src/client/UserSettingModal.ts
@@ -823,6 +823,34 @@ export class UserSettingModal extends BaseModal {
         @change=${this.toggleCursorCostLabel}
       ></setting-toggle>
 
+      <!-- 🖱️ Hold Middle-Click Upgrade -->
+      <setting-toggle
+        label="${translateText("user_setting.hold_middle_click_label")}"
+        description="${translateText("user_setting.hold_middle_click_desc")}"
+        id="hold-middle-click-upgrade-toggle"
+        .checked=${this.userSettings.holdMiddleClickUpgrade()}
+        @change=${() => {
+          this.userSettings.toggleHoldMiddleClickUpgrade();
+          this.requestUpdate();
+        }}
+      ></setting-toggle>
+
+      <!-- ⏱️ Upgrade Hold Speed -->
+      <setting-slider
+        label="${translateText("user_setting.hold_middle_click_speed_label")}"
+        description="${translateText(
+          "user_setting.hold_middle_click_speed_desc",
+        )}"
+        min="50"
+        max="500"
+        step="25"
+        unit="ms"
+        .value=${this.userSettings.holdMiddleClickUpgradeSpeed()}
+        @change=${(e: CustomEvent<{ value: number }>) => {
+          this.userSettings.setHoldMiddleClickUpgradeSpeed(e.detail.value);
+        }}
+      ></setting-slider>
+
       <!-- 🖱️ Left Click Menu -->
       <setting-toggle
         label="${translateText("user_setting.left_click_label")}"
diff --git a/src/client/components/baseComponents/setting/SettingSlider.ts b/src/client/components/baseComponents/setting/SettingSlider.ts
index 071cdc2d45..dc5d0c0025 100644
--- a/src/client/components/baseComponents/setting/SettingSlider.ts
+++ b/src/client/components/baseComponents/setting/SettingSlider.ts
@@ -5,6 +5,7 @@ import { customElement, property } from "lit/decorators.js";
 export class SettingSlider extends LitElement {
   @property() label = "Setting";
   @property() description = "";
+  @property() unit = "%";
   @property({ type: Number }) value = 0;
   @property({ type: Number }) min = 0;
   @property({ type: Number }) max = 100;
@@ -65,7 +66,7 @@ export class SettingSlider extends LitElement {
           <div class="flex items-center gap-2 w-full">
             <span
               class="text-white font-bold text-sm shrink-0 text-right min-w-[3ch]"
-              >${this.value}%</span
+              >${this.value}${this.unit}</span
             >
             <input
               type="range"
diff --git a/src/core/game/UserSettings.ts b/src/core/game/UserSettings.ts
index 5062c79365..6520f89a6b 100644
--- a/src/core/game/UserSettings.ts
+++ b/src/core/game/UserSettings.ts
@@ -159,6 +159,25 @@ export class UserSettings {
     return this.getBool("settings.leftClickOpensMenu", false);
   }
 
+  holdMiddleClickUpgrade() {
+    return this.getBool("settings.holdMiddleClickUpgrade", true);
+  }
+
+  holdMiddleClickUpgradeSpeed(): number {
+    return this.getFloat("settings.holdMiddleClickUpgradeSpeed", 150);
+  }
+
+  toggleHoldMiddleClickUpgrade() {
+    this.setBool(
+      "settings.holdMiddleClickUpgrade",
+      !this.holdMiddleClickUpgrade(),
+    );
+  }
+
+  setHoldMiddleClickUpgradeSpeed(value: number): void {
+    this.setFloat("settings.holdMiddleClickUpgradeSpeed", value);
+  }
+
   territoryPatterns() {
     return this.getBool("settings.territoryPatterns", true);
   }