diff --git a/src/main/ipc/files.js b/src/main/ipc/files.js
index be0b236..83ecd97 100644
--- a/src/main/ipc/files.js
+++ b/src/main/ipc/files.js
@@ -92,9 +92,10 @@ function register() {
     return { restored, errors };
   });
 
-  ipcMain.handle('rename-files', async (_event, { folderPath, files, prefix, digits }) => {
+  ipcMain.handle('rename-files', async (_event, { folderPath, files, prefix, digits, postfix = '' }) => {
     const errors = [];
     const pad = (n) => String(n + 1).padStart(digits, '0');
+    const suffix = postfix ? `_${postfix}` : '';
 
     // 1단계: 임시 이름으로 이동 (충돌 방지)
     const tmpMap = [];
@@ -113,7 +114,7 @@ function register() {
     // 2단계: 최종 이름으로 이동
     const renamed = [];
     for (const { tmp, ext, idx } of tmpMap) {
-      const newName = `${prefix}_${pad(idx)}${ext}`;
+      const newName = `${prefix}_${pad(idx)}${suffix}${ext}`;
       const dest = path.join(folderPath, newName);
       try {
         fs.renameSync(tmp, dest);
diff --git a/src/renderer/grid.js b/src/renderer/grid.js
index 53508e0..4084783 100644
--- a/src/renderer/grid.js
+++ b/src/renderer/grid.js
@@ -11,6 +11,7 @@ const fileCount     = document.getElementById('file-count');
 const selCount      = document.getElementById('sel-count');
 const inputPrefix   = document.getElementById('input-prefix');
 const inputDigits   = document.getElementById('input-digits');
+const inputPostfix  = document.getElementById('input-postfix');
 
 let _cardObserver = null;
 
@@ -111,7 +112,7 @@ export function updateNumberBadges() {
 }
 
 export function updateNewNameLabels() {
-  const format = getNameFormat(inputPrefix, inputDigits);
+  const format = getNameFormat(inputPrefix, inputDigits, 3, inputPostfix);
   Array.from(grid.children).forEach((card, i) => {
     const el   = card.querySelector('.card-new-name');
     const file = state.files[i];
diff --git a/src/renderer/index.html b/src/renderer/index.html
index 5575eea..5fba393 100644
--- a/src/renderer/index.html
+++ b/src/renderer/index.html
@@ -45,6 +45,8 @@
       <span class="format-sep">_</span>
       <input type="number" id="input-digits" value="4" min="1" max="6" />
       <span class="format-sep">자리 순번</span>
+      <span class="format-sep">_</span>
+      <input type="text" id="input-postfix" maxlength="3" size="3" placeholder="접미사" />
       <span class="format-arrow">→</span>
       <span id="preview-name">photo_001.jpg</span>
       <span id="sel-count"></span>
diff --git a/src/renderer/rename.js b/src/renderer/rename.js
index a559643..df8c992 100644
--- a/src/renderer/rename.js
+++ b/src/renderer/rename.js
@@ -8,6 +8,7 @@ import { buildSequentialName, getNameFormat }            from './utils/file-name
 
 const inputPrefix            = document.getElementById('input-prefix');
 const inputDigits            = document.getElementById('input-digits');
+const inputPostfix           = document.getElementById('input-postfix');
 const renameConfirmModal     = document.getElementById('rename-confirm-modal');
 const renameConfirmSelectedTitle = renameConfirmModal.querySelector('.rename-title-selected');
 const renameConfirmAllTitle      = renameConfirmModal.querySelector('.rename-title-all');
@@ -30,8 +31,8 @@ renameConfirmModal.addEventListener('modal:closed', () => {
 
 export async function doRename() {
   if (!state.files.length || !state.currentFolder) return;
-  const { prefix, digits } = getNameFormat(inputPrefix, inputDigits);
-  const format = { prefix, digits };
+  const { prefix, digits, postfix } = getNameFormat(inputPrefix, inputDigits, 3, inputPostfix);
+  const format = { prefix, digits, postfix };
 
   const selectedArr   = [...state.selectedIdxs].sort((a, b) => a - b);
   const filesToRename = selectedArr.length > 0
@@ -75,6 +76,7 @@ export async function doRename() {
       files: filesToRename,
       prefix,
       digits,
+      postfix,
     });
     hideLoading();
     if (result.errors.length) {
diff --git a/src/renderer/renderer.js b/src/renderer/renderer.js
index 45b6e0d..aebf236 100644
--- a/src/renderer/renderer.js
+++ b/src/renderer/renderer.js
@@ -27,6 +27,7 @@ const btnSortDate      = document.getElementById('btn-sort-date');
 const btnRename        = document.getElementById('btn-rename');
 const inputPrefix      = document.getElementById('input-prefix');
 const inputDigits      = document.getElementById('input-digits');
+const inputPostfix     = document.getElementById('input-postfix');
 const previewName      = document.getElementById('preview-name');
 const dirPath          = document.getElementById('dir-path');
 const rubberBand       = document.getElementById('rubber-band');
@@ -113,6 +114,7 @@ window.api.onFullscreenChange((isFullscreen) => {
 // ── 버튼 / 키보드 이벤트 ─────────────────────────
 inputPrefix.addEventListener('input', updatePreview);
 inputDigits.addEventListener('input', updatePreview);
+inputPostfix.addEventListener('input', updatePreview);
 btnOpen.addEventListener('click', () => {
   log('ui', 'open button clicked');
   folderController.openFolder();
@@ -146,7 +148,9 @@ initKeyboardShortcuts({
 function updatePreview() {
   const prefix = inputPrefix.value.trim() || 'photo';
   const digits = clampDigits(inputDigits.value);
+  const postfix = inputPostfix.value.trim();
   const ext    = state.files.length ? getExtension(state.files[0].name) : 'jpg';
-  previewName.textContent = `${prefix}_${'1'.padStart(digits, '0')}.${ext}`;
+  const suffix = postfix ? `_${postfix}` : '';
+  previewName.textContent = `${prefix}_${'1'.padStart(digits, '0')}${suffix}.${ext}`;
   updateNewNameLabels();
 }
diff --git a/src/renderer/style.css b/src/renderer/style.css
index 338063d..aab3083 100644
--- a/src/renderer/style.css
+++ b/src/renderer/style.css
@@ -216,6 +216,7 @@ main {
 #format-bar input:focus { border-color: var(--accent); }
 #input-prefix { width: 160px; }
 #input-digits { width: 50px; text-align: center; }
+#input-postfix { width: 54px; }
 .format-sep { color: var(--muted); font-family: 'JetBrains Mono', monospace; font-size: 14px; }
 .format-arrow { color: var(--muted); font-size: 12px; }
 #preview-name {
diff --git a/src/renderer/utils/file-names.js b/src/renderer/utils/file-names.js
index 4458a7a..95e7096 100644
--- a/src/renderer/utils/file-names.js
+++ b/src/renderer/utils/file-names.js
@@ -7,14 +7,17 @@ export function clampDigits(value, fallback = 3) {
   return Math.max(1, Math.min(6, parseInt(value, 10) || fallback));
 }
 
-export function buildSequentialName(fileName, index, { prefix, digits }) {
+export function buildSequentialName(fileName, index, { prefix, digits, postfix = '' }) {
   const ext = getExtension(fileName);
-  return `${prefix}_${String(index + 1).padStart(digits, '0')}.${ext}`;
+  const sequence = `${prefix}_${String(index + 1).padStart(digits, '0')}`;
+  const suffix = postfix ? `_${postfix}` : '';
+  return `${sequence}${suffix}.${ext}`;
 }
 
-export function getNameFormat(prefixInput, digitsInput, digitsFallback = 3) {
+export function getNameFormat(prefixInput, digitsInput, digitsFallback = 3, postfixInput = null) {
   return {
     prefix: prefixInput.value.trim() || 'photo',
     digits: clampDigits(digitsInput.value, digitsFallback),
+    postfix: postfixInput?.value.trim() || '',
   };
 }