diff --git a/locales/en-US.yml b/locales/en-US.yml
index 5f588efd443a..28fa37c25417 100644
--- a/locales/en-US.yml
+++ b/locales/en-US.yml
@@ -311,6 +311,7 @@ folderName: "Folder name"
 createFolder: "Create a folder"
 renameFolder: "Rename this folder"
 deleteFolder: "Delete this folder"
+folder: "Folder"
 addFile: "Add a file"
 emptyDrive: "Your Drive is empty"
 emptyFolder: "This folder is empty"
diff --git a/locales/index.d.ts b/locales/index.d.ts
index 242a7275e387..1617b67bea86 100644
--- a/locales/index.d.ts
+++ b/locales/index.d.ts
@@ -311,6 +311,7 @@ export interface Locale {
     "createFolder": string;
     "renameFolder": string;
     "deleteFolder": string;
+    "folder": string;
     "addFile": string;
     "emptyDrive": string;
     "emptyFolder": string;
diff --git a/locales/ja-JP.yml b/locales/ja-JP.yml
index 87a47dbd331f..02d63eb59b1d 100644
--- a/locales/ja-JP.yml
+++ b/locales/ja-JP.yml
@@ -308,6 +308,7 @@ folderName: "フォルダー名"
 createFolder: "フォルダーを作成"
 renameFolder: "フォルダー名を変更"
 deleteFolder: "フォルダーを削除"
+folder: "フォルダー"
 addFile: "ファイルを追加"
 emptyDrive: "ドライブは空です"
 emptyFolder: "フォルダーは空です"
diff --git a/packages/frontend/src/components/MkEmojiPicker.section.vue b/packages/frontend/src/components/MkEmojiPicker.section.vue
index 08297ea5baef..fda847bef97d 100644
--- a/packages/frontend/src/components/MkEmojiPicker.section.vue
+++ b/packages/frontend/src/components/MkEmojiPicker.section.vue
@@ -5,9 +5,10 @@ SPDX-License-Identifier: AGPL-3.0-only
 
 <template>
 <!-- このコンポーネントの要素のclassは親から利用されるのでむやみに弄らないこと -->
-<section>
+<!-- フォルダの中にはカスタム絵文字だけ（Unicode絵文字もこっち） -->
+<section v-if="!hasChildSection">
 	<header class="_acrylic" @click="shown = !shown">
-		<i class="toggle ti-fw" :class="shown ? 'ti ti-chevron-down' : 'ti ti-chevron-up'"></i> <slot></slot> ({{ emojis.length }})
+		<i class="toggle ti-fw" :class="shown ? 'ti ti-chevron-down' : 'ti ti-chevron-up'"></i> <slot></slot> (<i class="ti ti-icons"></i>:{{ emojis.length }})
 	</header>
 	<div v-if="shown" class="body">
 		<button
@@ -23,15 +24,52 @@ SPDX-License-Identifier: AGPL-3.0-only
 		</button>
 	</div>
 </section>
+<!-- フォルダの中にはカスタム絵文字やフォルダがある -->
+<section v-else>
+  <header class="_acrylic" @click="shown = !shown">
+    <i class="toggle ti-fw" :class="shown ? 'ti ti-chevron-down' : 'ti ti-chevron-up'"></i> <slot></slot> (<i class="ti ti-folder"></i>:{{ customEmojiTree.length }} <i class="ti ti-icons"></i>:{{ emojis.length }})
+  </header>
+  <div v-if="shown" class="body">
+    <button
+        v-for="emoji in emojis"
+        :key="emoji"
+        :data-emoji="emoji"
+        class="_button item"
+        @pointerenter="computeButtonTitle"
+        @click="emit('chosen', emoji, $event)"
+    >
+      <MkCustomEmoji v-if="emoji[0] === ':'" class="emoji" :name="emoji" :normal="true"/>
+      <MkEmoji v-else class="emoji" :emoji="emoji" :normal="true"/>
+    </button>
+  </div>
+  <div v-if="shown" style="padding-left: 9px;">
+    <MkEmojiPickerSection
+        v-for="child in customEmojiTree"
+        :key="`custom:${child.value}`"
+        :initialShown="initialShown"
+        :emojis="computed(() => customEmojis.filter(e => e.category === child.category).map(e => `:${e.name}:`))"
+        :hasChildSection="child.children.length !== 0"
+        :customEmojiTree="child.children"
+        @chosen="nestedChosen"
+    >
+			{{ child.value || i18n.ts.other }}
+    </MkEmojiPickerSection>
+  </div>
+</section>
 </template>
 
 <script lang="ts" setup>
 import { ref, computed, Ref } from 'vue';
-import { getEmojiName } from '@/scripts/emojilist.js';
+import { CustomEmojiFolderTree, getEmojiName } from '@/scripts/emojilist.js';
+import { i18n } from '../i18n.js';
+import { customEmojis } from '@/custom-emojis.js';
+import MkEmojiPickerSection from '@/components/MkEmojiPicker.section.vue';
 
 const props = defineProps<{
 	emojis: string[] | Ref<string[]>;
 	initialShown?: boolean;
+	hasChildSection?: boolean;
+	customEmojiTree?: CustomEmojiFolderTree[];
 }>();
 
 const emit = defineEmits<{
@@ -49,4 +87,7 @@ function computeButtonTitle(ev: MouseEvent): void {
 	elm.title = getEmojiName(emoji) ?? emoji;
 }
 
+function nestedChosen(emoji: any, ev?: MouseEvent) {
+	emit('chosen', emoji, ev);
+}
 </script>
diff --git a/packages/frontend/src/components/MkEmojiPicker.vue b/packages/frontend/src/components/MkEmojiPicker.vue
index c7636a4f61a8..027315b49960 100644
--- a/packages/frontend/src/components/MkEmojiPicker.vue
+++ b/packages/frontend/src/components/MkEmojiPicker.vue
@@ -73,18 +73,20 @@ SPDX-License-Identifier: AGPL-3.0-only
 		<div v-once class="group">
 			<header class="_acrylic">{{ i18n.ts.customEmojis }}</header>
 			<XSection
-				v-for="category in customEmojiCategories"
-				:key="`custom:${category}`"
+				v-for="child in customEmojiFolderRoot.children"
+				:key="`custom:${child.value}`"
 				:initialShown="false"
-				:emojis="computed(() => customEmojis.filter(e => category === null ? (e.category === 'null' || !e.category) : e.category === category).filter(filterAvailable).map(e => `:${e.name}:`))"
+				:emojis="computed(() => customEmojis.filter(e => child.value === '' ? (e.category === 'null' || !e.category) : e.category === child.value).filter(filterAvailable).map(e => `:${e.name}:`))"
+        :hasChildSection="child.children.length !== 0"
+        :customEmojiTree="child.children"
 				@chosen="chosen"
 			>
-				{{ category || i18n.ts.other }}
+				{{ child.value || i18n.ts.other }}
 			</XSection>
 		</div>
 		<div v-once class="group">
 			<header class="_acrylic">{{ i18n.ts.emoji }}</header>
-			<XSection v-for="category in categories" :key="category" :emojis="emojiCharByCategory.get(category) ?? []" @chosen="chosen">{{ category }}</XSection>
+			<XSection v-for="category in categories" :key="category" :emojis="emojiCharByCategory.get(category) ?? []" :hasChildSection="false" @chosen="chosen">{{ category }}</XSection>
 		</div>
 	</div>
 	<div class="tabs">
@@ -100,7 +102,14 @@ SPDX-License-Identifier: AGPL-3.0-only
 import { ref, shallowRef, computed, watch, onMounted } from 'vue';
 import * as Misskey from 'misskey-js';
 import XSection from '@/components/MkEmojiPicker.section.vue';
-import { emojilist, emojiCharByCategory, UnicodeEmojiDef, unicodeEmojiCategories as categories, getEmojiName } from '@/scripts/emojilist.js';
+import {
+  emojilist,
+  emojiCharByCategory,
+  UnicodeEmojiDef,
+  unicodeEmojiCategories as categories,
+  getEmojiName,
+  CustomEmojiFolderTree
+} from '@/scripts/emojilist.js';
 import MkRippleEffect from '@/components/MkRippleEffect.vue';
 import * as os from '@/os.js';
 import { isTouchUsing } from '@/scripts/touch.js';
@@ -144,6 +153,34 @@ const searchResultCustom = ref<Misskey.entities.CustomEmoji[]>([]);
 const searchResultUnicode = ref<UnicodeEmojiDef[]>([]);
 const tab = ref<'index' | 'custom' | 'unicode' | 'tags'>('index');
 
+const customEmojiFolderRoot: CustomEmojiFolderTree = { value: "", category: "", children: [] };
+
+function parseAndMergeCategories(input: string, root: CustomEmojiFolderTree): CustomEmojiFolderTree {
+	const parts = input.split('/').map(p => p.trim());
+	let currentNode: CustomEmojiFolderTree = root;
+
+	for (const part of parts) {
+		let existingNode = currentNode.children.find((node) => node.value === part);
+		if (!existingNode) {
+			const newNode: CustomEmojiFolderTree = { value: part, category: input, children: [] };
+			currentNode.children.push(newNode);
+			existingNode = newNode;
+		}
+
+		currentNode = existingNode;
+	}
+
+	return currentNode;
+}
+
+customEmojiCategories.value.forEach(ec => {
+  if (ec !== null) {
+    parseAndMergeCategories(ec, customEmojiFolderRoot);
+  }
+});
+
+parseAndMergeCategories('', customEmojiFolderRoot);
+
 watch(q, () => {
 	if (emojisEl.value) emojisEl.value.scrollTop = 0;
 
diff --git a/packages/frontend/src/scripts/emojilist.ts b/packages/frontend/src/scripts/emojilist.ts
index 4159da84c883..8885bf4b7f5f 100644
--- a/packages/frontend/src/scripts/emojilist.ts
+++ b/packages/frontend/src/scripts/emojilist.ts
@@ -43,3 +43,9 @@ export function getEmojiName(char: string): string | null {
 		return emojilist[idx].name;
 	}
 }
+
+export interface CustomEmojiFolderTree {
+	value: string;
+	category: string;
+	children: CustomEmojiFolderTree[];
+}