diff --git a/packages/backend/src/core/RoleService.ts b/packages/backend/src/core/RoleService.ts
index b250eeee21..f15c5ab45f 100644
--- a/packages/backend/src/core/RoleService.ts
+++ b/packages/backend/src/core/RoleService.ts
@@ -737,6 +737,20 @@ export class RoleService implements OnApplicationShutdown, OnModuleInit {
 		}
 	}
 
+	@bindThis
+	public async clone(role: MiRole, moderator?: MiUser): Promise<MiRole> {
+		let newName = `${role.name} (cloned)`;
+
+		if (newName.length > 256) {
+			newName = newName.slice(0, 256);
+		}
+
+		return this.create({
+			...role,
+			name: newName,
+		}, moderator);
+	}
+
 	@bindThis
 	public async delete(role: MiRole, moderator?: MiUser): Promise<void> {
 		await this.rolesRepository.delete({ id: role.id });
diff --git a/packages/backend/src/server/api/endpoint-list.ts b/packages/backend/src/server/api/endpoint-list.ts
index a78c3e9ae6..962055052d 100644
--- a/packages/backend/src/server/api/endpoint-list.ts
+++ b/packages/backend/src/server/api/endpoint-list.ts
@@ -88,6 +88,7 @@ export * as 'admin/reset-password' from './endpoints/admin/reset-password.js';
 export * as 'admin/resolve-abuse-user-report' from './endpoints/admin/resolve-abuse-user-report.js';
 export * as 'admin/roles/assign' from './endpoints/admin/roles/assign.js';
 export * as 'admin/roles/create' from './endpoints/admin/roles/create.js';
+export * as 'admin/roles/clone' from './endpoints/admin/roles/clone.js';
 export * as 'admin/roles/delete' from './endpoints/admin/roles/delete.js';
 export * as 'admin/roles/list' from './endpoints/admin/roles/list.js';
 export * as 'admin/roles/show' from './endpoints/admin/roles/show.js';
diff --git a/packages/backend/src/server/api/endpoints/admin/roles/clone.ts b/packages/backend/src/server/api/endpoints/admin/roles/clone.ts
new file mode 100644
index 0000000000..83a7a54c3a
--- /dev/null
+++ b/packages/backend/src/server/api/endpoints/admin/roles/clone.ts
@@ -0,0 +1,60 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { RoleService } from '@/core/RoleService.js';
+import { DI } from '@/di-symbols.js';
+import type { RolesRepository } from '@/models/_.js';
+import { Endpoint } from '@/server/api/endpoint-base.js';
+import { ApiError } from '@/server/api/error.js';
+import { RoleEntityService } from '@/core/entities/RoleEntityService.js';
+
+export const meta = {
+	tags: ['admin', 'role'],
+
+	requireCredential: true,
+	requireAdmin: true,
+	kind: 'write:admin:roles',
+
+	res: {
+		type: 'object',
+		optional: false, nullable: false,
+		ref: 'Role',
+	},
+
+	errors: {
+		noSuchRole: {
+			message: 'No such role.',
+			code: 'NO_SUCH_ROLE',
+			id: '93cc897a-b5f9-431f-b9b7-ee59035a5aed',
+		},
+	},
+} as const;
+
+export const paramDef = {
+	type: 'object',
+	properties: {
+		roleId: { type: 'string', format: 'misskey:id' },
+	},
+	required: [
+		'roleId',
+	],
+} as const;
+
+@Injectable()
+export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-disable-line import/no-default-export
+	constructor(
+		@Inject(DI.rolesRepository)
+		private rolesRepository: RolesRepository,
+		private roleEntityService: RoleEntityService,
+		private roleService: RoleService,
+	) {
+		super(meta, paramDef, async (ps, me) => {
+			const role = await this.rolesRepository.findOneBy({ id: ps.roleId });
+			if (role == null) {
+				throw new ApiError(meta.errors.noSuchRole);
+			}
+
+			const cloned = await this.roleService.clone(role, me);
+
+			return this.roleEntityService.pack(cloned, me);
+		});
+	}
+}
diff --git a/packages/backend/test/unit/RoleService.ts b/packages/backend/test/unit/RoleService.ts
index 2afe22618d..534556b056 100644
--- a/packages/backend/test/unit/RoleService.ts
+++ b/packages/backend/test/unit/RoleService.ts
@@ -983,4 +983,50 @@ describe('RoleService', () => {
 			expect(notificationService.createNotification).not.toHaveBeenCalled();
 		});
 	});
+
+	describe('clone', () => {
+		test('clones an role', async () => {
+			const role = await createRole({
+				name: 'original role',
+				color: '#ff0000',
+				policies: {
+					canManageCustomEmojis: {
+						useDefault: false,
+						priority: 0,
+						value: true,
+					},
+				},
+			});
+
+			const clonedRole = await roleService.clone(role);
+
+			expect(clonedRole).toBeDefined();
+			expect(clonedRole.id).not.toBe(role.id);
+			expect(clonedRole.name).toBe(`${role.name} (cloned)`);
+
+			expect(clonedRole).toEqual(expect.objectContaining({
+				color: role.color,
+				policies: {
+					canManageCustomEmojis: {
+						useDefault: false,
+						priority: 0,
+						value: true,
+					},
+				},
+			}));
+		});
+
+		test('clones a roll with a too long name', async () => {
+			const role = await createRole({
+				name: 'a'.repeat(254),
+			});
+
+			const clonedRole = await roleService.clone(role);
+
+			expect(clonedRole).toBeDefined();
+			expect(clonedRole.id).not.toBe(role.id);
+			expect(clonedRole.name).toBe(`${role.name} (`);
+			expect(clonedRole.name.length).toBe(256);
+		});
+	});
 });