diff --git a/src/features/study/group/api/apply-group-study.ts b/src/features/study/group/api/apply-group-study.ts
new file mode 100644
index 00000000..372dfed8
--- /dev/null
+++ b/src/features/study/group/api/apply-group-study.ts
@@ -0,0 +1,17 @@
+import { axiosInstance } from '@/shared/tanstack-query/axios';
+import {
+  ApplyGroupStudyRequest,
+  ApplyGroupStudyResponse,
+} from './group-study-types';
+
+// 그룹 스터디 신청 요청
+export const applyGroupStudy = async ({
+  groupStudyId,
+  answer,
+}: ApplyGroupStudyRequest): Promise<ApplyGroupStudyResponse> => {
+  const res = await axiosInstance.post(`/group-studies/${groupStudyId}/apply`, {
+    answer,
+  });
+
+  return res.data;
+};
diff --git a/src/features/study/group/api/group-study-types.ts b/src/features/study/group/api/group-study-types.ts
index 4edc08b5..219f78be 100644
--- a/src/features/study/group/api/group-study-types.ts
+++ b/src/features/study/group/api/group-study-types.ts
@@ -7,6 +7,24 @@ import {
   THUMBNAIL_EXTENSION,
 } from '../const/group-study-const';
 
+// 그룹 스터디 신청 상태
+type ApplicationStatus = 'PENDING' | 'APPROVED' | 'REJECTED' | 'KICKED';
+
+// 그룹 스터디 신청 Request 타입
+export interface ApplyGroupStudyRequest {
+  groupStudyId: number;
+  answer: string[];
+}
+
+// 그룹 스터디 신청 Response 타입
+export interface ApplyGroupStudyResponse {
+  applyId: number;
+  applicantId: number;
+  groupStudyId: number;
+  status: ApplicationStatus;
+  createdAt: string;
+}
+
 export type StudyType = (typeof STUDY_TYPES)[number];
 export type TargetRole = (typeof TARGET_ROLE_OPTIONS)[number];
 export type ExperienceLevel = (typeof EXPERIENCE_LEVEL_OPTIONS)[number];
diff --git a/src/features/study/group/model/use-apply-group-study.tsx b/src/features/study/group/model/use-apply-group-study.tsx
new file mode 100644
index 00000000..f015af51
--- /dev/null
+++ b/src/features/study/group/model/use-apply-group-study.tsx
@@ -0,0 +1,9 @@
+import { useMutation } from '@tanstack/react-query';
+import { applyGroupStudy } from '../api/apply-group-study';
+
+// 그룹 스터디 신청 훅
+export const useApplyGroupStudyMutation = () => {
+  return useMutation({
+    mutationFn: applyGroupStudy,
+  });
+};
diff --git a/src/features/study/group/ui/apply-group-study-modal.tsx b/src/features/study/group/ui/apply-group-study-modal.tsx
new file mode 100644
index 00000000..922bd197
--- /dev/null
+++ b/src/features/study/group/ui/apply-group-study-modal.tsx
@@ -0,0 +1,226 @@
+'use client';
+
+import { zodResolver } from '@hookform/resolvers/zod';
+import { XIcon } from 'lucide-react';
+import { useState } from 'react';
+
+import { useController, useForm } from 'react-hook-form';
+import { z } from 'zod';
+import Button from '@/shared/ui/button';
+import Checkbox from '@/shared/ui/checkbox';
+import { Modal } from '@/shared/ui/modal';
+import { useApplyGroupStudyMutation } from '../model/use-apply-group-study';
+
+interface ApplyGroupStudyModalProps {
+  groupStudyId: number;
+  title: string;
+  questions: string[];
+}
+
+export default function ApplyGroupStudyModal({
+  groupStudyId,
+  title,
+  questions,
+}: ApplyGroupStudyModalProps) {
+  const [open, setOpen] = useState<boolean>(false);
+
+  return (
+    <Modal.Root open={open} onOpenChange={setOpen}>
+      <Modal.Trigger asChild>
+        <Button size="large">신청하기</Button>
+      </Modal.Trigger>
+
+      <Modal.Portal>
+        <Modal.Overlay />
+        <Modal.Content>
+          <Modal.Header className="border-border-default flex justify-between border-b">
+            <Modal.Title className="font-designer-20b text-text-strong">
+              스터디 신청서 작성하기
+            </Modal.Title>
+            <Modal.Close onClick={() => setOpen(false)}>
+              <XIcon />
+            </Modal.Close>
+          </Modal.Header>
+
+          <ApplyGroupStudyForm
+            groupStudyId={groupStudyId}
+            title={title}
+            questions={questions}
+            onClose={() => setOpen(false)}
+          />
+        </Modal.Content>
+      </Modal.Portal>
+    </Modal.Root>
+  );
+}
+
+const ApplyGroupStudyFormSchema = z.object({
+  answer: z.array(
+    z.string().min(1, '답변을 작성해주세요.'), // 각 항목에 최소 1글자 이상
+  ),
+  agree: z
+    .boolean()
+    .refine((val) => val === true, { message: '참여 규칙에 동의해야 합니다.' }),
+});
+
+type ApplyGroupStudyFormData = z.infer<typeof ApplyGroupStudyFormSchema>;
+
+function ApplyGroupStudyForm({
+  groupStudyId,
+  title,
+  questions,
+  onClose,
+}: {
+  groupStudyId: number;
+  title: string;
+  questions: string[];
+  onClose: () => void;
+}) {
+  const {
+    register,
+    handleSubmit,
+    control,
+    formState: { errors },
+  } = useForm<ApplyGroupStudyFormData>({
+    resolver: zodResolver(ApplyGroupStudyFormSchema),
+    defaultValues: {
+      answer: Array(questions.length).fill(''),
+    },
+  });
+
+  // ✅ checkbox를 controller로 제어
+  const {
+    field: { value: checked, onChange: onToggle },
+  } = useController({
+    name: 'agree',
+    control,
+  });
+
+  const { mutate: applyGroupStudy } = useApplyGroupStudyMutation();
+
+  const onSubmit = (data: ApplyGroupStudyFormData) => {
+    const { answer } = data;
+
+    applyGroupStudy(
+      { answer, groupStudyId },
+      {
+        onSuccess: () => {
+          alert('스터디 신청이 완료되었습니다.');
+          onClose();
+        },
+      },
+    );
+  };
+
+  return (
+    <>
+      <Modal.Body className="flex flex-col gap-400 px-400 py-300">
+        <h2 className="font-designer-20b text-text-default">{title}</h2>
+
+        <div className="flex flex-col gap-250">
+          <span className="font-designer-16b text-text-default">
+            리더의 질문
+          </span>
+
+          <form
+            id="apply-group-study"
+            className="flex flex-col gap-300"
+            onSubmit={handleSubmit(onSubmit)}
+          >
+            {questions.map((question, index) => (
+              <div key={question} className="flex flex-col gap-150">
+                <label
+                  htmlFor={`question-${index}`}
+                  className="font-designer-15b text-text-default"
+                >
+                  {`${index + 1}. ${question}`}
+                </label>
+
+                <div className="flex flex-col gap-75">
+                  <textarea
+                    id={`question-${index}`}
+                    className={`rounded-100 ${errors.answer?.[index] ? 'border-border-error' : 'border-border-default'} font-designer-16m text-text-default min-h-[150px] w-full border p-150 focus-visible:ring-0 focus-visible:outline-none`}
+                    placeholder="리더의 질문에 답변을 작성해주세요."
+                    {...register(`answer.${index}`)}
+                  />
+                  {errors.answer?.[index] && (
+                    <span className="text-text-error font-designer-13r">
+                      {errors.answer[index].message}
+                    </span>
+                  )}
+                </div>
+              </div>
+            ))}
+          </form>
+        </div>
+
+        <div className="text-text-default bg-background-alternative rounded-150 flex flex-col gap-300 px-400 py-300">
+          <h3 className="font-designer-20b">스터디 참여 규칙을 준수해주세요</h3>
+
+          <ul className="font-designer-16m text-text-subtle flex flex-col gap-100">
+            <li className="flex items-center gap-150">
+              <span>·</span>
+              <span>모집 공고의 정보는 사실에 기반해 작성해야 합니다.</span>
+            </li>
+            <li className="flex items-center gap-150">
+              <span>·</span>
+              <span>진행 기간과 모임 빈도를 명확히 안내해야 합니다.</span>
+            </li>
+            <li className="flex items-center gap-150">
+              <span>·</span>
+              <span>
+                스터디 개설 후 최소 1회 이상 정기 모임을 진행해야 합니다.
+              </span>
+            </li>
+            <li className="flex items-center gap-150">
+              <span>·</span>
+              <span>스터디원과의 약속을 존중하고 성실히 운영해야 합니다.</span>
+            </li>
+            <li className="flex items-center gap-150">
+              <span>·</span>
+              <span>
+                타인의 개인정보 및 자료를 무단으로 공유하거나 외부 유출해서는 안
+                됩니다.
+              </span>
+            </li>
+            <li className="flex items-center gap-150">
+              <span>·</span>
+              <span>
+                플랫폼의 운영 정책 및 커뮤니티 가이드를 준수해야 합니다.
+              </span>
+            </li>
+          </ul>
+
+          <div
+            className={`${errors.agree ? 'border-border-error' : 'border-border-default'} rounded-100 flex items-center justify-between border p-300`}
+          >
+            <div className="flex items-center gap-100">
+              <span className="text-text-default font-designer-16b">
+                참여 규칙을 확인하시고 동의해 주시겠습니까?
+              </span>
+              <span className="font-designer-13m text-text-error">필수</span>
+            </div>
+
+            <Checkbox id="agree" checked={checked} onToggle={onToggle} />
+          </div>
+        </div>
+      </Modal.Body>
+
+      <Modal.Footer className="flex justify-end gap-100">
+        <Modal.Close asChild>
+          <Button color="secondary" size="large" onClick={onClose}>
+            취소
+          </Button>
+        </Modal.Close>
+        <Button
+          color="primary"
+          size="large"
+          type="submit"
+          form="apply-group-study"
+        >
+          신청하기
+        </Button>
+      </Modal.Footer>
+    </>
+  );
+}