diff --git a/frontend/src/components/Compose.tsx b/frontend/src/components/Compose.tsx
new file mode 100644
index 00000000..f83cbeea
--- /dev/null
+++ b/frontend/src/components/Compose.tsx
@@ -0,0 +1,83 @@
+import { useState } from 'react'
+import { mailApi } from '../api/mailApi'
+import { useMailStore } from '../store/mailStore'
+
+export default function Compose() {
+  const { replyTo, closeCompose, username } = useMailStore()
+  const [to, setTo] = useState(replyTo?.sender_addr || '')
+  const [cc, setCc] = useState('')
+  const [subject, setSubject] = useState(
+    replyTo ? (replyTo.subject.startsWith('Re:') ? replyTo.subject : `Re: ${replyTo.subject}`) : ''
+  )
+  const [body, setBody] = useState(
+    replyTo
+      ? `\n\n---\n${replyTo.date}에 ${replyTo.sender} (${replyTo.sender_addr}) 님이 작성:\n${replyTo.body_text || '(HTML 메일)'}\n`
+      : ''
+  )
+  const [sending, setSending] = useState(false)
+  const [error, setError] = useState('')
+  const [success, setSuccess] = useState(false)
+  const [showCc, setShowCc] = useState(false)
+
+  const send = async () => {
+    if (!to.trim() || !subject.trim()) { setError('받는사람과 제목은 필수입니다'); return }
+    setSending(true); setError('')
+    try {
+      await mailApi.send({ to, cc: cc || undefined, subject, body })
+      setSuccess(true)
+      setTimeout(closeCompose, 1500)
+    } catch (e: any) {
+      setError(e.response?.data?.detail || '발송에 실패했습니다')
+    } finally { setSending(false) }
+  }
+
+  return (
+    <div className="compose-overlay" onClick={e => e.target === e.currentTarget && closeCompose()}>
+      <div className="compose-box">
+        <div className="compose-header">
+          <span>✏️ {replyTo ? '답장' : '새 메일'}</span>
+          <button className="compose-close" onClick={closeCompose}>✕</button>
+        </div>
+
+        <div className="compose-fields">
+          <div className="compose-field">
+            <label>보내는 사람</label>
+            <span className="compose-from">{username}</span>
+          </div>
+          <div className="compose-field">
+            <label>받는 사람</label>
+            <input value={to} onChange={e => setTo(e.target.value)} placeholder="수신자 이메일" />
+            <button className="btn-cc-toggle" onClick={() => setShowCc(v => !v)}>참조</button>
+          </div>
+          {showCc && (
+            <div className="compose-field">
+              <label>참조</label>
+              <input value={cc} onChange={e => setCc(e.target.value)} placeholder="참조 이메일" />
+            </div>
+          )}
+          <div className="compose-field">
+            <label>제목</label>
+            <input value={subject} onChange={e => setSubject(e.target.value)} placeholder="제목 입력" />
+          </div>
+        </div>
+
+        <textarea
+          className="compose-body"
+          value={body}
+          onChange={e => setBody(e.target.value)}
+          placeholder="내용을 입력하세요..."
+        />
+
+        {error && <div className="compose-error">⚠️ {error}</div>}
+        {success && <div className="compose-success">✅ 발송 완료!</div>}
+
+        <div className="compose-footer">
+          <button className="btn-send" onClick={send} disabled={sending}>
+            {sending ? '발송 중...' : '📨 보내기'}
+          </button>
+          <button className="btn-cancel" onClick={closeCompose}>취소</button>
+        </div>
+      </div>
+    </div>
+  )
+}