diff --git a/frontend/src/routes/library/+page.svelte b/frontend/src/routes/library/+page.svelte
index ef0353d..bdb6063 100644
--- a/frontend/src/routes/library/+page.svelte
+++ b/frontend/src/routes/library/+page.svelte
@@ -152,13 +152,43 @@
     window.open(`/api/documents/${doc.id}/preview?token=${getAccessToken()}&download=true`);
   }
 
-  // ─── 업로드 ───
+  // ─── 업로드 (버튼 + 드래그) ───
 
+  const MAX_UPLOAD_BYTES = 100 * 1024 * 1024;
   let fileInput;
   let uploadingCount = $state(0);
+  let dragging = $state(false);
+  let dragCounter = 0;
 
-  async function handleUpload(e) {
-    const files = Array.from(e.target.files || []);
+  onMount(() => {
+    function onDragEnter(e) { e.preventDefault(); dragCounter++; dragging = true; }
+    function onDragOver(e) { e.preventDefault(); }
+    function onDragLeave(e) { e.preventDefault(); dragCounter--; if (dragCounter <= 0) { dragging = false; dragCounter = 0; } }
+    function onDrop(e) { e.preventDefault(); dragging = false; dragCounter = 0; uploadFiles(e.dataTransfer?.files); }
+    window.addEventListener('dragenter', onDragEnter);
+    window.addEventListener('dragover', onDragOver);
+    window.addEventListener('dragleave', onDragLeave);
+    window.addEventListener('drop', onDrop);
+    return () => {
+      window.removeEventListener('dragenter', onDragEnter);
+      window.removeEventListener('dragover', onDragOver);
+      window.removeEventListener('dragleave', onDragLeave);
+      window.removeEventListener('drop', onDrop);
+    };
+  });
+
+  function handleUpload(e) {
+    uploadFiles(e.target.files);
+    fileInput.value = '';
+  }
+
+  async function uploadFiles(fileList) {
+    const allFiles = Array.from(fileList || []);
+    const files = allFiles.filter(f => f.size <= MAX_UPLOAD_BYTES);
+    const tooLarge = allFiles.filter(f => f.size > MAX_UPLOAD_BYTES);
+    if (tooLarge.length > 0) {
+      addToast('error', `100MB 초과 파일 ${tooLarge.length}건 제외됨`);
+    }
     if (files.length === 0) return;
 
     uploadingCount = files.length;
@@ -178,7 +208,6 @@
     }
 
     uploadingCount = 0;
-    fileInput.value = '';
 
     if (success > 0) {
       addToast('success', `${success}건 업로드 완료`);
@@ -460,3 +489,16 @@
     </main>
   </div>
 </div>
+
+<!-- 드래그 업로드 오버레이 -->
+{#if dragging}
+  <div class="fixed inset-0 z-50 bg-accent/10 border-2 border-dashed border-accent flex items-center justify-center">
+    <div class="bg-surface rounded-xl px-8 py-6 shadow-xl text-center">
+      <Upload size={32} class="mx-auto mb-2 text-accent" />
+      <p class="text-sm font-medium text-accent">자료실에 파일 업로드</p>
+      {#if activePath}
+        <p class="text-xs text-dim mt-1">경로: {activePath}</p>
+      {/if}
+    </div>
+  </div>
+{/if}