diff --git a/packages/backend/src/core/activitypub/ApRendererService.ts b/packages/backend/src/core/activitypub/ApRendererService.ts
index 5617a29bab22..914809506743 100644
--- a/packages/backend/src/core/activitypub/ApRendererService.ts
+++ b/packages/backend/src/core/activitypub/ApRendererService.ts
@@ -183,6 +183,9 @@ export class ApRendererService {
 				// || emoji.originalUrl してるのは後方互換性のため（publicUrlはstringなので??はだめ）
 				url: emoji.publicUrl || emoji.originalUrl,
 			},
+			_misskey_license: {
+				freeText: emoji.license
+			},
 		};
 	}
 
diff --git a/packages/backend/src/core/activitypub/models/ApNoteService.ts b/packages/backend/src/core/activitypub/models/ApNoteService.ts
index eb2e771a38fc..9b8f217810be 100644
--- a/packages/backend/src/core/activitypub/models/ApNoteService.ts
+++ b/packages/backend/src/core/activitypub/models/ApNoteService.ts
@@ -414,6 +414,8 @@ export class ApNoteService {
 						originalUrl: tag.icon.url,
 						publicUrl: tag.icon.url,
 						updatedAt: new Date(),
+						// _misskey_license が存在しなければ `null`
+						license: (tag._misskey_license?.freeText ?? null)
 					});
 
 					const emoji = await this.emojisRepository.findOneBy({ host, name });
@@ -435,6 +437,8 @@ export class ApNoteService {
 				publicUrl: tag.icon.url,
 				updatedAt: new Date(),
 				aliases: [],
+				// _misskey_license が存在しなければ `null`
+				license: (tag._misskey_license?.freeText ?? null)
 			});
 		}));
 	}
diff --git a/packages/backend/src/core/activitypub/type.ts b/packages/backend/src/core/activitypub/type.ts
index 7496315f0970..72732b01dfe8 100644
--- a/packages/backend/src/core/activitypub/type.ts
+++ b/packages/backend/src/core/activitypub/type.ts
@@ -242,6 +242,11 @@ export interface IApEmoji extends IObject {
 	type: 'Emoji';
 	name: string;
 	updated: string;
+	// Misskey拡張。後方互換性のためにoptional。
+	// 将来の拡張性を考慮してobjectにしている
+	_misskey_license?: {
+		freeText: string | null;
+	};
 }
 
 export const isEmoji = (object: IObject): object is IApEmoji =>