diff --git a/apps/readest-app/src/app/reader/components/annotator/HighlightOptions.tsx b/apps/readest-app/src/app/reader/components/annotator/HighlightOptions.tsx
index fd176b7f..b216359b 100644
--- a/apps/readest-app/src/app/reader/components/annotator/HighlightOptions.tsx
+++ b/apps/readest-app/src/app/reader/components/annotator/HighlightOptions.tsx
@@ -9,7 +9,15 @@ import { useResponsiveSize } from '@/hooks/useResponsiveSize';
 import { saveSysSettings } from '@/helpers/settings';
 
 const styles = ['highlight', 'underline', 'squiggly'] as HighlightStyle[];
-const colors = ['red', 'violet', 'blue', 'green', 'yellow'] as HighlightColor[];
+const defaultColors = ['red', 'violet', 'blue', 'green', 'yellow'] as HighlightColor[];
+
+const getColorHex = (
+  customColors: Record<HighlightColor, string>,
+  color: HighlightColor,
+): string => {
+  if (color.startsWith('#')) return color;
+  return customColors[color as HighlightColor] ?? color;
+};
 
 interface HighlightOptionsProps {
   isVertical: boolean;
@@ -41,6 +49,7 @@ const HighlightOptions: React.FC<HighlightOptionsProps> = ({
   const einkBgColor = isDarkMode ? '#000000' : '#ffffff';
   const einkFgColor = isDarkMode ? '#ffffff' : '#000000';
   const customColors = globalReadSettings.customHighlightColors;
+  const userColors = globalReadSettings.userHighlightColors ?? [];
   const [selectedStyle, setSelectedStyle] = useState<HighlightStyle>(_selectedStyle);
   const [selectedColor, setSelectedColor] = useState<HighlightColor>(_selectedColor);
   const size16 = useResponsiveSize(16);
@@ -55,6 +64,7 @@ const HighlightOptions: React.FC<HighlightOptionsProps> = ({
     setSelectedColor(globalReadSettings.highlightStyles[style]);
     onHandleHighlight(true);
   };
+
   const handleSelectColor = (color: HighlightColor) => {
     const newGlobalReadSettings = {
       ...globalReadSettings,
@@ -65,10 +75,11 @@ const HighlightOptions: React.FC<HighlightOptionsProps> = ({
     setSelectedColor(color);
     onHandleHighlight(true);
   };
+
   return (
     <div
       className={clsx(
-        'highlight-options absolute flex items-center justify-between',
+        'highlight-options absolute flex items-center justify-between gap-4',
         isVertical ? 'flex-col' : 'flex-row',
       )}
       style={{
@@ -106,7 +117,9 @@ const HighlightOptions: React.FC<HighlightOptionsProps> = ({
                 height: size16,
                 ...(style === 'highlight' &&
                   selectedStyle === 'highlight' && {
-                    backgroundColor: isEink ? einkFgColor : customColors[selectedColor],
+                    backgroundColor: isEink
+                      ? einkFgColor
+                      : getColorHex(customColors, selectedColor),
                     color: isEink ? einkBgColor : '#d1d5db',
                     paddingTop: '2px',
                   }),
@@ -123,7 +136,7 @@ const HighlightOptions: React.FC<HighlightOptionsProps> = ({
                     selectedStyle === style
                       ? isEink
                         ? einkFgColor
-                        : customColors[selectedColor]
+                        : getColorHex(customColors, selectedColor)
                       : '#d1d5db',
                   ...(style === 'squiggly' && { textDecorationStyle: 'wavy' }),
                 }),
@@ -138,31 +151,39 @@ const HighlightOptions: React.FC<HighlightOptionsProps> = ({
 
       <div
         className={clsx(
-          'not-eink:bg-gray-700 eink-bordered flex items-center justify-center gap-2 rounded-3xl',
-          isVertical ? 'flex-col py-2' : 'flex-row px-2',
+          'not-eink:bg-gray-700 eink-bordered flex items-center gap-2 rounded-3xl',
+          isVertical ? 'flex-col overflow-y-auto py-2' : 'flex-row overflow-x-auto px-2',
         )}
-        style={isVertical ? { width: size28 } : { height: size28 }}
+        style={{
+          ...(isVertical ? { width: size28 } : { height: size28 }),
+          scrollbarWidth: 'none',
+          msOverflowStyle: 'none',
+        }}
       >
-        {colors
+        {defaultColors
+          .concat(userColors)
           .filter((c) => (isEink ? selectedColor === c : true))
           .map((color) => (
-            <button
-              key={color}
-              onClick={() => handleSelectColor(color)}
-              style={{
-                width: size16,
-                height: size16,
-                backgroundColor: selectedColor !== color ? customColors[color] : 'transparent',
-              }}
-              className='rounded-full p-0'
-            >
-              {selectedColor === color && (
-                <FaCheckCircle
-                  size={size16}
-                  style={{ fill: isEink ? einkFgColor : customColors[color] }}
-                />
-              )}
-            </button>
+            <div key={color} className='flex items-center justify-center'>
+              <button
+                key={color}
+                onClick={() => handleSelectColor(color)}
+                style={{
+                  width: size16,
+                  height: size16,
+                  backgroundColor:
+                    selectedColor !== color ? customColors[color] || color : 'transparent',
+                }}
+                className='rounded-full p-0'
+              >
+                {selectedColor === color && (
+                  <FaCheckCircle
+                    size={size16}
+                    style={{ fill: isEink ? einkFgColor : customColors[color] || color }}
+                  />
+                )}
+              </button>
+            </div>
           ))}
       </div>
     </div>
diff --git a/apps/readest-app/src/app/reader/utils/annotatorUtil.ts b/apps/readest-app/src/app/reader/utils/annotatorUtil.ts
index 5df2d248..2468c3f7 100644
--- a/apps/readest-app/src/app/reader/utils/annotatorUtil.ts
+++ b/apps/readest-app/src/app/reader/utils/annotatorUtil.ts
@@ -2,9 +2,12 @@ import { HIGHLIGHT_COLOR_HEX } from '@/services/constants';
 import { HighlightColor } from '@/types/book';
 import { SystemSettings } from '@/types/settings';
 
-export const getHighlightColorHex = (settings: SystemSettings, color?: HighlightColor) => {
-  if (!color) return color;
-
+export const getHighlightColorHex = (
+  settings: SystemSettings,
+  color?: HighlightColor,
+): string | undefined => {
+  if (!color) return undefined;
+  if (color.startsWith('#')) return color;
   const customColors = settings.globalReadSettings.customHighlightColors;
   return customColors?.[color] ?? HIGHLIGHT_COLOR_HEX[color];
 };
diff --git a/apps/readest-app/src/components/settings/ColorPanel.tsx b/apps/readest-app/src/components/settings/ColorPanel.tsx
index cf99a4b9..072b90eb 100644
--- a/apps/readest-app/src/components/settings/ColorPanel.tsx
+++ b/apps/readest-app/src/components/settings/ColorPanel.tsx
@@ -61,6 +61,9 @@ const ColorPanel: React.FC<SettingsPanelPanelProp> = ({ bookKey, onRegisterReset
   const [customTtsHighlightColors, setCustomTtsHighlightColors] = useState(
     settings.globalReadSettings.customTtsHighlightColors || [],
   );
+  const [userHighlightColors, setUserHighlightColors] = useState(
+    settings.globalReadSettings.userHighlightColors || [],
+  );
 
   const {
     textures: customTextures,
@@ -87,6 +90,7 @@ const ColorPanel: React.FC<SettingsPanelPanelProp> = ({ bookKey, onRegisterReset
     setBackgroundOpacity(0.6);
     setBackgroundSize('cover');
     setCustomHighlightColors(HIGHLIGHT_COLOR_HEX);
+    setUserHighlightColors([]);
   };
 
   useEffect(() => {
@@ -253,6 +257,13 @@ const ColorPanel: React.FC<SettingsPanelPanelProp> = ({ bookKey, onRegisterReset
     saveSettings(envConfig, settings);
   };
 
+  const handleUserHighlightColorsChange = (colors: string[]) => {
+    setUserHighlightColors(colors);
+    settings.globalReadSettings.userHighlightColors = colors;
+    setSettings(settings);
+    saveSettings(envConfig, settings);
+  };
+
   return (
     <div className='my-4 w-full space-y-6'>
       {showCustomThemeEditor ? (
@@ -311,7 +322,9 @@ const ColorPanel: React.FC<SettingsPanelPanelProp> = ({ bookKey, onRegisterReset
 
           <HighlightColorsEditor
             customHighlightColors={customHighlightColors}
+            userHighlightColors={userHighlightColors}
             onChange={handleHighlightColorsChange}
+            onUserColorsChange={handleUserHighlightColorsChange}
           />
 
           <TTSHighlightStyleEditor
diff --git a/apps/readest-app/src/components/settings/color/HighlightColorsEditor.tsx b/apps/readest-app/src/components/settings/color/HighlightColorsEditor.tsx
index d0104104..ded4be3a 100644
--- a/apps/readest-app/src/components/settings/color/HighlightColorsEditor.tsx
+++ b/apps/readest-app/src/components/settings/color/HighlightColorsEditor.tsx
@@ -1,49 +1,137 @@
-import React from 'react';
+import React, { useState } from 'react';
+import { MdClose } from 'react-icons/md';
 import { HighlightColor } from '@/types/book';
 import { useTranslation } from '@/hooks/useTranslation';
 import ColorInput from './ColorInput';
 
+const MAX_USER_HIGHLIGHT_COLORS = 10;
+
 interface HighlightColorsEditorProps {
   customHighlightColors: Record<HighlightColor, string>;
+  userHighlightColors: string[];
   onChange: (colors: Record<HighlightColor, string>) => void;
+  onUserColorsChange: (colors: string[]) => void;
 }
 
 const HighlightColorsEditor: React.FC<HighlightColorsEditorProps> = ({
   customHighlightColors,
+  userHighlightColors,
   onChange,
+  onUserColorsChange,
 }) => {
   const _ = useTranslation();
+  const [newColor, setNewColor] = useState('#808080');
 
   const handleColorChange = (color: HighlightColor, value: string) => {
     const updated = { ...customHighlightColors, [color]: value };
     onChange(updated);
   };
 
+  const handleAddUserColor = () => {
+    if (userHighlightColors.length >= MAX_USER_HIGHLIGHT_COLORS) return;
+    if (!userHighlightColors.includes(newColor)) {
+      const updatedColors = [...userHighlightColors, newColor];
+      onUserColorsChange(updatedColors);
+    }
+  };
+
+  const handleDeleteUserColor = (hex: string) => {
+    const updatedColors = userHighlightColors.filter((c) => c !== hex);
+    onUserColorsChange(updatedColors);
+  };
+
+  const handleUserColorChange = (oldHex: string, newHex: string) => {
+    const updatedColors = userHighlightColors.map((c) => (c === oldHex ? newHex : c));
+    onUserColorsChange(updatedColors);
+  };
+
   return (
     <div>
       <h2 className='mb-2 font-medium'>{_('Highlight Colors')}</h2>
       <div className='card border-base-200 bg-base-100 overflow-visible border p-4 shadow'>
-        <div className='grid grid-cols-3 gap-3 sm:grid-cols-5'>
-          {(['red', 'violet', 'blue', 'green', 'yellow'] as HighlightColor[]).map(
-            (color, index, array) => {
-              const position =
-                index === 0 ? 'left' : index === array.length - 1 ? 'right' : 'center';
-              return (
-                <div key={color} className='flex flex-col items-center gap-2'>
+        <div className='space-y-4'>
+          <div className='grid grid-cols-3 gap-3 sm:grid-cols-5'>
+            {(['red', 'violet', 'blue', 'green', 'yellow'] as HighlightColor[]).map(
+              (color, index, array) => {
+                const position =
+                  index === 0 ? 'left' : index === array.length - 1 ? 'right' : 'center';
+                return (
+                  <div key={color} className='flex flex-col items-center gap-2'>
+                    <div
+                      className='border-base-300 h-8 w-8 rounded-full border-2 shadow-sm'
+                      style={{ backgroundColor: customHighlightColors[color] }}
+                    />
+                    <ColorInput
+                      label=''
+                      value={customHighlightColors[color]!}
+                      compact={true}
+                      pickerPosition={position}
+                      onChange={(value: string) => handleColorChange(color, value)}
+                    />
+                  </div>
+                );
+              },
+            )}
+          </div>
+
+          {(userHighlightColors.length > 0 || true) && (
+            <div className='border-base-200 border-t pt-4'>
+              <div className='mb-3 flex items-center justify-between'>
+                <span className='text-sm font-medium'>
+                  {_('Custom Colors')} ({userHighlightColors.length}/{MAX_USER_HIGHLIGHT_COLORS})
+                </span>
+                <div className='flex items-center gap-2'>
                   <div
-                    className='border-base-300 h-8 w-8 rounded-full border-2 shadow-sm'
-                    style={{ backgroundColor: customHighlightColors[color] }}
+                    className='border-base-300 h-6 w-6 rounded-full border-2 shadow-sm'
+                    style={{ backgroundColor: newColor }}
                   />
                   <ColorInput
                     label=''
-                    value={customHighlightColors[color]}
+                    value={newColor}
                     compact={true}
-                    pickerPosition={position}
-                    onChange={(value: string) => handleColorChange(color, value)}
+                    pickerPosition='right'
+                    onChange={setNewColor}
                   />
+                  <button
+                    onClick={handleAddUserColor}
+                    disabled={
+                      userHighlightColors.includes(newColor) ||
+                      userHighlightColors.length >= MAX_USER_HIGHLIGHT_COLORS
+                    }
+                    className='btn btn-ghost btn-sm gap-1 bg-transparent disabled:bg-transparent disabled:opacity-40'
+                  >
+                    <span className='text-xs'>{_('Add')}</span>
+                  </button>
                 </div>
-              );
-            },
+              </div>
+
+              {userHighlightColors.length > 0 && (
+                <div className='grid grid-cols-3 gap-3 sm:grid-cols-5'>
+                  {userHighlightColors.map((hex, index) => (
+                    <div key={hex} className='group relative flex flex-col items-center gap-2'>
+                      <div
+                        className='border-base-300 h-8 w-8 rounded-full border-2 shadow-sm'
+                        style={{ backgroundColor: hex }}
+                      />
+                      <ColorInput
+                        label=''
+                        value={hex}
+                        compact={true}
+                        pickerPosition={index === 0 ? 'left' : 'center'}
+                        onChange={(value: string) => handleUserColorChange(hex, value)}
+                      />
+                      <button
+                        onClick={() => handleDeleteUserColor(hex)}
+                        className='absolute -right-1 -top-1 rounded-full bg-red-500 p-0.5 text-white opacity-0 transition-opacity hover:opacity-100 group-hover:opacity-100'
+                        title={_('Delete')}
+                      >
+                        <MdClose size={12} />
+                      </button>
+                    </div>
+                  ))}
+                </div>
+              )}
+            </div>
           )}
         </div>
       </div>
diff --git a/apps/readest-app/src/services/constants.ts b/apps/readest-app/src/services/constants.ts
index 7a46cf47..9ab75a43 100644
--- a/apps/readest-app/src/services/constants.ts
+++ b/apps/readest-app/src/services/constants.ts
@@ -125,6 +125,7 @@ export const DEFAULT_READSETTINGS: ReadSettings = {
     squiggly: 'blue',
   },
   customHighlightColors: HIGHLIGHT_COLOR_HEX,
+  userHighlightColors: [],
   customTtsHighlightColors: [],
 };
 
diff --git a/apps/readest-app/src/types/book.ts b/apps/readest-app/src/types/book.ts
index 6f2ecd44..6aaac7c9 100644
--- a/apps/readest-app/src/types/book.ts
+++ b/apps/readest-app/src/types/book.ts
@@ -15,7 +15,8 @@ export type BookFormat =
   | 'MD';
 export type BookNoteType = 'bookmark' | 'annotation' | 'excerpt';
 export type HighlightStyle = 'highlight' | 'underline' | 'squiggly';
-export type HighlightColor = 'red' | 'yellow' | 'green' | 'blue' | 'violet';
+// Predefined highlight colors, can be extended with custom hex colors
+export type HighlightColor = 'red' | 'yellow' | 'green' | 'blue' | 'violet' | string;
 
 export const FIXED_LAYOUT_FORMATS: Set<BookFormat> = new Set(['PDF', 'CBZ']);
 
diff --git a/apps/readest-app/src/types/settings.ts b/apps/readest-app/src/types/settings.ts
index ca266f7f..0f845ab2 100644
--- a/apps/readest-app/src/types/settings.ts
+++ b/apps/readest-app/src/types/settings.ts
@@ -34,6 +34,7 @@ export interface ReadSettings {
   highlightStyle: HighlightStyle;
   highlightStyles: Record<HighlightStyle, HighlightColor>;
   customHighlightColors: Record<HighlightColor, string>;
+  userHighlightColors: string[];
   customTtsHighlightColors: string[];
   customThemes: CustomTheme[];
 }