diff --git a/src/App.tsx b/src/App.tsx
index 85c5c43..74f2ab5 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -6,12 +6,14 @@ import { DateRangeView } from './examples/DateRangeView';
 import { InteractiveDateRange } from './examples/InteractiveDateRange';
 import { CompactYear } from './examples/CompactYear';
 import { ComprehensiveColorScheme } from './examples/ComprehensiveColorScheme';
+import { LocaleSupport } from './examples/LocaleSupport';
 import styles from './App.module.scss';
 
 const App: React.FC = () => {
   return (
     <div className={styles.container}>
       <DateRangePicker />
+      <LocaleSupport />
       <ComprehensiveColorScheme />
       <SingleMonth />
       <WeekView />
diff --git a/src/components/calendar/Day/index.tsx b/src/components/calendar/Day/index.tsx
index f5365bc..2396f97 100644
--- a/src/components/calendar/Day/index.tsx
+++ b/src/components/calendar/Day/index.tsx
@@ -18,7 +18,8 @@ export const Day: React.FC<DayProps> = ({
   fontProportion = 100,
   magnify = false,
   activeColors,
-  colorScheme
+  colorScheme,
+  locale
 }) => {
   const isInteractive = Boolean(onSelect || onHover);
 
@@ -102,7 +103,7 @@ export const Day: React.FC<DayProps> = ({
       {headerStyle !== 'none' && (
         <div className={headerClasses} style={headerCustomStyles}>
           <div className={styles.Day__HeaderText}>
-            {getDayLabel(date, headerStyle)}
+            {getDayLabel(date, headerStyle, locale)}
           </div>
         </div>
       )}
diff --git a/src/components/calendar/Month/index.tsx b/src/components/calendar/Month/index.tsx
index af27c59..c52f7da 100644
--- a/src/components/calendar/Month/index.tsx
+++ b/src/components/calendar/Month/index.tsx
@@ -1,5 +1,6 @@
 import React from 'react';
 import { startOfMonth, startOfWeek, addDays, addWeeks, endOfMonth, format } from 'date-fns';
+import { enUS } from 'date-fns/locale';
 import { MonthProps, HeaderStyle } from '../../../types/calendar';
 import { Week } from '../Week';
 import styles from './Month.module.scss';
@@ -20,7 +21,8 @@ export const Month: React.FC<MonthProps> = ({
   magnify = false,
   activeColors,
   activeDates,
-  colorScheme
+  colorScheme,
+  locale = enUS
 }) => {
   const monthStart = startOfMonth(date);
   const start = startOfWeek(monthStart, { weekStartsOn: 1 });
@@ -51,6 +53,7 @@ export const Month: React.FC<MonthProps> = ({
         activeColors={activeColors}
         activeDates={activeDates}
         colorScheme={colorScheme}
+        locale={locale}
       />
     );
     current = addWeeks(current, 1);
@@ -58,7 +61,7 @@ export const Month: React.FC<MonthProps> = ({
 
   return (
     <div className={styles.Month}>
-      <h2 className={styles.Month__Title}>{format(date, 'MMMM yyyy')}</h2>
+      <h2 className={styles.Month__Title}>{format(date, 'MMMM yyyy', { locale })}</h2>
       <div className={classNames(styles.Month__Container, {
         [styles['Month__Container--row']]: direction === 'row',
         [styles['Month__Container--column']]: direction === 'column'
@@ -77,7 +80,7 @@ export const Month: React.FC<MonthProps> = ({
                     [styles['Month__DayHeader--weekend']]: isWeekend
                   })}
                 >
-                  {format(dayDate, 'EEEEE')}
+                  {format(dayDate, 'EEEEE', { locale })}
                 </div>
               );
             })}
diff --git a/src/components/calendar/Week/index.tsx b/src/components/calendar/Week/index.tsx
index f9f48f7..8f5322b 100644
--- a/src/components/calendar/Week/index.tsx
+++ b/src/components/calendar/Week/index.tsx
@@ -20,7 +20,8 @@ export const Week: React.FC<WeekProps> = ({
   magnify = false,
   activeColors,
   activeDates = [],
-  colorScheme
+  colorScheme,
+  locale
 }) => {
   const allDays = Array.from({ length: 7 }, (_, i) => {
     const date = addDays(startDate, i);
@@ -63,6 +64,7 @@ export const Week: React.FC<WeekProps> = ({
             magnify={magnify}
             activeColors={activeColors}
             colorScheme={colorScheme}
+            locale={locale}
           />
         </div>
       );
@@ -81,6 +83,7 @@ export const Week: React.FC<WeekProps> = ({
           magnify={magnify}
           activeColors={activeColors}
           colorScheme={colorScheme}
+          locale={locale}
         />
       </div>
     );
diff --git a/src/components/calendar/Year/index.tsx b/src/components/calendar/Year/index.tsx
index 81f6324..c62af01 100644
--- a/src/components/calendar/Year/index.tsx
+++ b/src/components/calendar/Year/index.tsx
@@ -17,7 +17,8 @@ export const Year: React.FC<YearProps> = ({
   magnify = false,
   activeColors,
   activeDates,
-  colorScheme
+  colorScheme,
+  locale
 }) => {
   const months = Array.from({ length: 12 }, (_, index) => {
     const monthDate = new Date(year, index, 1);
@@ -39,6 +40,7 @@ export const Year: React.FC<YearProps> = ({
         activeColors={activeColors}
         activeDates={activeDates}
         colorScheme={colorScheme}
+        locale={locale}
       />
     );
   });
diff --git a/src/components/calendar/utils.ts b/src/components/calendar/utils.ts
index 319d32a..fc3449c 100644
--- a/src/components/calendar/utils.ts
+++ b/src/components/calendar/utils.ts
@@ -1,5 +1,6 @@
 import { HeaderStyle } from '../../types/calendar';
-import { format } from 'date-fns';
+import { format, Locale } from 'date-fns';
+import { enUS } from 'date-fns/locale';
 
 export const getHeightByHeaderStyle = (headerStyle: HeaderStyle) => {
   const baseHeights: Record<HeaderStyle, [string, string]> = {
@@ -29,22 +30,30 @@ export const getMinWidthByHeaderStyle = (headerStyle: HeaderStyle) => {
   return `min-width: ${baseWidths[headerStyle]};`;
 };
 
-export const getDayLabel = (date: Date, headerStyle: HeaderStyle): string => {
-  const day = format(date, 'EEEE');
+export const getDayLabel = (date: Date, headerStyle: HeaderStyle, locale: Locale = enUS): string => {
+  const day = format(date, 'EEEE', { locale });
+  
   switch (headerStyle) {
     case 'expanded':
       return day.toUpperCase();
     case 'compacted':
-      return day.slice(0, 3).toUpperCase();
+      // Use EEE format for proper 3-letter abbreviation in the locale
+      return format(date, 'EEE', { locale }).toUpperCase();
     case 'tiny':
-      if (day === 'Thursday') return 'T';
-      if (day === 'Tuesday') return 't';
-      if (day === 'Saturday') return 's';
-      if (day === 'Sunday') return 'S';
-      if (day === 'Monday') return 'M';
-      if (day === 'Wednesday') return 'W';
-      if (day === 'Friday') return 'F';
-      return day[0];
+      // Use EEEEE format for single letter abbreviation when available
+      // Fallback to first letter for better locale support
+      const singleLetter = format(date, 'EEEEE', { locale });
+      
+      // For English, handle special cases (Thursday/Tuesday, Saturday/Sunday)
+      if (locale.code === 'en-US' || locale.code === 'en') {
+        const dayName = format(date, 'EEEE', { locale });
+        if (dayName === 'Thursday') return 'T';
+        if (dayName === 'Tuesday') return 't';
+        if (dayName === 'Saturday') return 's';
+        if (dayName === 'Sunday') return 'S';
+      }
+      
+      return singleLetter.toUpperCase();
     default:
       return day;
   }
diff --git a/src/examples/LocaleSupport.tsx b/src/examples/LocaleSupport.tsx
new file mode 100644
index 0000000..215c05e
--- /dev/null
+++ b/src/examples/LocaleSupport.tsx
@@ -0,0 +1,135 @@
+import React, { useState } from 'react';
+import { Year } from '../components/calendar/Year';
+import { Controls } from '../components/calendar/Controls';
+import { HeaderStyle, MonthCutoffType, DaySize } from '../types/calendar';
+import styles from './Examples.module.scss';
+import { Locale } from 'date-fns';
+import { 
+  enUS, 
+  es, 
+  fr, 
+  de, 
+  it, 
+  pt, 
+  ja, 
+  ko, 
+  zhCN,
+  ru,
+  ar,
+  nl,
+  pl,
+  tr,
+  sv,
+  nb
+} from 'date-fns/locale';
+
+export const LocaleSupport: React.FC = () => {
+  const [dayHeaderStyle, setDayHeaderStyle] = useState<HeaderStyle>('tiny');
+  const [monthCutoff, setMonthCutoff] = useState<MonthCutoffType>('truncate');
+  const [size, setSize] = useState<DaySize>('l');
+  const [fontProportion, setFontProportion] = useState<number>(100);
+  const [magnify, setMagnify] = useState<boolean>(false);
+  const [selectedLocale, setSelectedLocale] = useState<string>('enUS');
+
+  const locales: Record<string, { locale: Locale; name: string }> = {
+    enUS: { locale: enUS, name: 'English (US)' },
+    es: { locale: es, name: 'Español' },
+    fr: { locale: fr, name: 'Français' },
+    de: { locale: de, name: 'Deutsch' },
+    it: { locale: it, name: 'Italiano' },
+    pt: { locale: pt, name: 'Português' },
+    ja: { locale: ja, name: '日本語' },
+    ko: { locale: ko, name: '한국어' },
+    zhCN: { locale: zhCN, name: '中文 (简体)' },
+    ru: { locale: ru, name: 'Русский' },
+    ar: { locale: ar, name: 'العربية' },
+    nl: { locale: nl, name: 'Nederlands' },
+    pl: { locale: pl, name: 'Polski' },
+    tr: { locale: tr, name: 'Türkçe' },
+    sv: { locale: sv, name: 'Svenska' },
+    nb: { locale: nb, name: 'Norsk' }
+  };
+
+  const activeDates = [
+    new Date(2025, 0, 1),  // New Year's Day
+    new Date(2025, 3, 21), // Spring
+    new Date(2025, 6, 14), // Bastille Day / Summer
+    new Date(2025, 9, 31), // Halloween
+    new Date(2025, 11, 25) // Christmas
+  ];
+
+  return (
+    <section className={styles.section}>
+      <h2 className={styles.sectionTitle}>International Locale Support</h2>
+      <p className={styles.sectionDescription}>
+        The calendar supports multiple languages through the date-fns locale system. 
+        Day names, month names, and date formats are automatically localized.
+      </p>
+      
+      <div className={styles.controlRow}>
+        <label className={styles.control}>
+          Language:
+          <select 
+            value={selectedLocale} 
+            onChange={(e) => setSelectedLocale(e.target.value)}
+            style={{ marginLeft: '8px', padding: '4px 8px' }}
+          >
+            {Object.entries(locales).map(([key, { name }]) => (
+              <option key={key} value={key}>{name}</option>
+            ))}
+          </select>
+        </label>
+      </div>
+      
+      <Controls
+        headerStyle={dayHeaderStyle}
+        monthCutoff={monthCutoff}
+        size={size}
+        fontProportion={fontProportion}
+        magnify={magnify}
+        onHeaderStyleChange={setDayHeaderStyle}
+        onMonthCutoffChange={setMonthCutoff}
+        onSizeChange={setSize}
+        onFontProportionChange={setFontProportion}
+        onMagnifyChange={setMagnify}
+      />
+      
+      <div className={styles.demoContainer}>
+        <Year 
+          year={2025}
+          dayHeaderStyle={dayHeaderStyle}
+          monthCutoff={monthCutoff}
+          weekendDays={[6, 0]}
+          size={size}
+          fontProportion={fontProportion}
+          magnify={magnify}
+          locale={locales[selectedLocale].locale}
+          activeDates={activeDates}
+        />
+      </div>
+      
+      <div className={styles.info}>
+        <h4>Localized Elements:</h4>
+        <ul>
+          <li>Month names (e.g., January, Janvier, Januar, 一月)</li>
+          <li>Day names in headers (Monday, Lundi, Montag, 月曜日)</li>
+          <li>Day abbreviations (Mon, Lun, Mo, 月)</li>
+          <li>Single letter days (M, L, M, 月)</li>
+        </ul>
+        
+        <h4 style={{ marginTop: '20px' }}>Header Style Examples:</h4>
+        <ul>
+          <li><strong>Expanded:</strong> Full day names (e.g., MONDAY, LUNDI, MONTAG)</li>
+          <li><strong>Compacted:</strong> 3-letter abbreviations (e.g., MON, LUN, MO)</li>
+          <li><strong>Tiny:</strong> Single letters with special handling for conflicts</li>
+          <li><strong>None:</strong> No day headers, only numbers</li>
+        </ul>
+        
+        <p style={{ marginTop: '20px', fontSize: '0.9em', color: '#666' }}>
+          Note: Some languages may show squares or incorrect characters if the required fonts 
+          are not installed on your system (especially for Arabic, Chinese, Japanese, and Korean).
+        </p>
+      </div>
+    </section>
+  );
+};
\ No newline at end of file
diff --git a/src/types/calendar.ts b/src/types/calendar.ts
index 9c25db9..00bc2b2 100644
--- a/src/types/calendar.ts
+++ b/src/types/calendar.ts
@@ -1,3 +1,5 @@
+import { Locale } from 'date-fns';
+
 export type DateRange = {
   startDate: Date | null;
   endDate: Date | null;
@@ -71,6 +73,7 @@ export interface YearProps {
   activeColors?: ActiveColors;
   activeDates?: Date[];
   colorScheme?: ColorScheme;
+  locale?: Locale;
 }
 
 export interface MonthProps {
@@ -89,6 +92,7 @@ export interface MonthProps {
   activeColors?: ActiveColors;
   activeDates?: Date[];
   colorScheme?: ColorScheme;
+  locale?: Locale;
 }
 
 export interface WeekProps {
@@ -106,6 +110,7 @@ export interface WeekProps {
   activeColors?: ActiveColors;
   activeDates?: Date[];
   colorScheme?: ColorScheme;
+  locale?: Locale;
 }
 
 export interface DayProps {
@@ -120,4 +125,5 @@ export interface DayProps {
   magnify?: boolean;
   activeColors?: ActiveColors;
   colorScheme?: ColorScheme;
+  locale?: Locale;
 }