diff --git a/src/features/topics/components/ConfirmModalTopicCard.tsx b/src/features/topics/components/ConfirmModalTopicCard.tsx
new file mode 100644
index 0000000..ffa8c87
--- /dev/null
+++ b/src/features/topics/components/ConfirmModalTopicCard.tsx
@@ -0,0 +1,49 @@
+import { useRef } from 'react'
+
+import { cn } from '@/shared/lib/utils'
+import { Badge, Card } from '@/shared/ui'
+import { NumberedCheckbox } from '@/shared/ui/NumberedCheckbox'
+
+type ConfirmModalTopicCardProps = {
+  title: string
+  topicTypeLabel: string
+  description: string
+  createdByNickname: string
+  topicId: number
+  isSelected: boolean
+}
+
+export default function ConfirmModalTopicCard({
+  title,
+  topicTypeLabel,
+  description,
+  createdByNickname,
+  topicId,
+  isSelected,
+}: ConfirmModalTopicCardProps) {
+  const checkboxRef = useRef<HTMLButtonElement>(null)
+
+  return (
+    <div className="cursor-pointer" onClick={() => checkboxRef.current?.click()}>
+      <Card
+        className={cn('flex gap-small items-start p-medium', isSelected && 'border-primary-200')}
+      >
+        <div className="flex items-center" onClick={(e) => e.stopPropagation()}>
+          <NumberedCheckbox id={topicId.toString()} ref={checkboxRef} />
+        </div>
+        <div className="flex flex-col gap-small flex-1">
+          <div className="flex justify-between items-start">
+            <div className="flex gap-xsmall items-center">
+              <p className="text-black typo-subtitle3">{title}</p>
+              <Badge size="small" color="grey">
+                {topicTypeLabel}
+              </Badge>
+            </div>
+          </div>
+          <p className="typo-body4 text-grey-700">{description}</p>
+          <p className="typo-body6 text-grey-600">제안 : {createdByNickname}</p>
+        </div>
+      </Card>
+    </div>
+  )
+}
diff --git a/src/features/topics/components/ConfirmTopicModal.tsx b/src/features/topics/components/ConfirmTopicModal.tsx
new file mode 100644
index 0000000..f12b01c
--- /dev/null
+++ b/src/features/topics/components/ConfirmTopicModal.tsx
@@ -0,0 +1,143 @@
+import { useState } from 'react'
+
+import { ConfirmModalTopicCard, TopicListSkeleton } from '@/features/topics/components'
+import { useConfirmTopics, useProposedTopics } from '@/features/topics/hooks'
+import {
+  Button,
+  Modal,
+  ModalBody,
+  ModalContent,
+  ModalFooter,
+  ModalHeader,
+  ModalTitle,
+  TextButton,
+} from '@/shared/ui'
+import { NumberedCheckboxGroup } from '@/shared/ui/NumberedCheckbox'
+import { useGlobalModalStore } from '@/store'
+
+export type ConfirmTopicModalProps = {
+  /** 모달 열림 상태 */
+  open: boolean
+  /** 모달 열림 상태 변경 핸들러 */
+  onOpenChange: (open: boolean) => void
+  gatheringId: number
+  meetingId: number
+}
+
+export default function ConfirmTopicModal({
+  open,
+  onOpenChange,
+  gatheringId,
+  meetingId,
+}: ConfirmTopicModalProps) {
+  const [selectedTopicIds, setSelectedTopicIds] = useState<string[]>([])
+
+  const { openConfirm, openError } = useGlobalModalStore()
+  const confirmMutation = useConfirmTopics()
+
+  // 모달 전용 독립 데이터 - 한 번에 전체 로드 (pageSize 크게)
+  const { data: topicsInfiniteData, isLoading } = useProposedTopics({
+    gatheringId,
+    meetingId,
+    pageSize: 100,
+  })
+
+  const topics = topicsInfiniteData?.pages.flatMap((page) => page.items) ?? []
+
+  const resetSelected = () => {
+    setSelectedTopicIds([])
+  }
+
+  const handleClose = () => {
+    resetSelected()
+    onOpenChange(false)
+  }
+
+  const handleConfirm = async () => {
+    const confirmed = await openConfirm(
+      '주제 확정',
+      `한 번 확정하면 이후에는 순서를 바꾸거나 주제를 추가하기 어려워요. \n이대로 확정할까요?`,
+      { confirmText: '확정하기' }
+    )
+
+    if (!confirmed) return
+
+    confirmMutation.mutate(
+      {
+        gatheringId,
+        meetingId,
+        topicIds: selectedTopicIds.map(Number),
+      },
+      {
+        onSuccess: () => {
+          handleClose()
+        },
+        onError: (error) => {
+          openError('확정 실패', error.userMessage)
+        },
+      }
+    )
+  }
+
+  return (
+    <Modal open={open} onOpenChange={handleClose}>
+      <ModalContent variant="wide" onInteractOutside={(e) => e.preventDefault()}>
+        <ModalHeader className="items-start">
+          <ModalTitle>
+            <div className="flex flex-col gap-base">
+              <p>주제 확정하기</p>
+              <div className="flex justify-between items-center">
+                <p className="typo-subtitle4 text-grey-600">확정할 주제를 순서대로 선택해주세요</p>
+                {selectedTopicIds.length > 0 && (
+                  <TextButton className="-mr-base" onClick={resetSelected}>
+                    전체해제
+                  </TextButton>
+                )}
+              </div>
+            </div>
+          </ModalTitle>
+        </ModalHeader>
+
+        <ModalBody className="flex flex-col gap-base">
+          {isLoading ? (
+            <TopicListSkeleton count={5} />
+          ) : (
+            <NumberedCheckboxGroup
+              value={selectedTopicIds}
+              onChange={setSelectedTopicIds}
+              className="flex flex-col gap-small"
+            >
+              {topics.map((topic) => (
+                <ConfirmModalTopicCard
+                  key={topic.topicId}
+                  title={topic.title}
+                  topicTypeLabel={topic.topicTypeLabel}
+                  description={topic.description}
+                  createdByNickname={topic.createdByInfo.nickname}
+                  topicId={topic.topicId}
+                  isSelected={selectedTopicIds.includes(topic.topicId.toString())}
+                />
+              ))}
+            </NumberedCheckboxGroup>
+          )}
+        </ModalBody>
+
+        <ModalFooter>
+          <div className="flex gap-large justify-between items-start flex-1">
+            <p className="typo-body4 text-grey-700 shrink-0">
+              선택 <span className="typo-body3 text-black">{selectedTopicIds.length}</span>개
+            </p>
+            <Button
+              size="medium"
+              className="w-full"
+              disabled={selectedTopicIds.length === 0 || confirmMutation.isPending}
+              onClick={handleConfirm}
+            >
+              확정하기
+            </Button>
+          </div>
+        </ModalFooter>
+      </ModalContent>
+    </Modal>
+  )
+}
diff --git a/src/features/topics/components/TopicHeader.tsx b/src/features/topics/components/TopicHeader.tsx
index 329d88d..5f43a9d 100644
--- a/src/features/topics/components/TopicHeader.tsx
+++ b/src/features/topics/components/TopicHeader.tsx
@@ -8,6 +8,8 @@ type ProposedHeaderProps = {
   actions: { canConfirm: boolean; canSuggest: boolean }
   confirmedTopic: boolean
   confirmedTopicDate: string | null
+  proposedTopicsCount: number
+  onOpenChange: (open: boolean) => void
 }
 
 type ConfirmedHeaderProps = {
@@ -50,8 +52,8 @@ export default function TopicHeader(props: TopicHeaderProps) {
           </div>
 
           <div className="flex gap-xsmall">
-            {props.actions.canConfirm && (
-              <Button variant="secondary" outline>
+            {props.actions.canConfirm && props.proposedTopicsCount > 0 && (
+              <Button variant="secondary" outline onClick={() => props.onOpenChange(true)}>
                 주제 확정하기
               </Button>
             )}
diff --git a/src/features/topics/components/index.ts b/src/features/topics/components/index.ts
index 5825bdb..e77446c 100644
--- a/src/features/topics/components/index.ts
+++ b/src/features/topics/components/index.ts
@@ -1,4 +1,6 @@
 export { default as ConfirmedTopicList } from './ConfirmedTopicList'
+export { default as ConfirmModalTopicCard } from './ConfirmModalTopicCard'
+export { default as ConfirmTopicModal } from './ConfirmTopicModal'
 export { default as DefaultTopicCard } from './DefaultTopicCard'
 export { default as EmptyTopicList } from './EmptyTopicList'
 export { default as ProposedTopicList } from './ProposedTopicList'
diff --git a/src/features/topics/hooks/index.ts b/src/features/topics/hooks/index.ts
index 6681b5b..672efba 100644
--- a/src/features/topics/hooks/index.ts
+++ b/src/features/topics/hooks/index.ts
@@ -1,5 +1,6 @@
 export * from './topicQueryKeys'
 export * from './useConfirmedTopics'
+export * from './useConfirmTopics'
 export * from './useCreateTopic'
 export * from './useDeleteTopic'
 export * from './useLikeTopic'
diff --git a/src/features/topics/hooks/useConfirmTopics.ts b/src/features/topics/hooks/useConfirmTopics.ts
new file mode 100644
index 0000000..ca2a2c7
--- /dev/null
+++ b/src/features/topics/hooks/useConfirmTopics.ts
@@ -0,0 +1,60 @@
+/**
+ * @file useConfirmTopics.ts
+ * @description 주제 확정 mutation 훅
+ */
+
+import { useMutation, useQueryClient } from '@tanstack/react-query'
+
+import { ApiError } from '@/api/errors'
+
+import { confirmTopics } from '../topics.api'
+import type { ConfirmTopicsParams, ConfirmTopicsResponse } from '../topics.types'
+import { topicQueryKeys } from './topicQueryKeys'
+
+/**
+ * 주제 확정 mutation 훅
+ *
+ * @description
+ * 선택한 주제들을 순서대로 확정하고 관련 쿼리 캐시를 무효화합니다.
+ * - 제안된 주제 리스트 캐시 무효화
+ * - 확정된 주제 리스트 캐시 무효화
+ *
+ * @example
+ * ```tsx
+ * const confirmMutation = useConfirmTopics()
+ * confirmMutation.mutate(
+ *   { gatheringId: 1, meetingId: 2, topicIds: [3, 1, 2] },
+ *   {
+ *     onSuccess: () => {
+ *       console.log('주제가 확정되었습니다.')
+ *     },
+ *     onError: (error) => {
+ *       console.error('확정 실패:', error.userMessage)
+ *     },
+ *   }
+ * )
+ * ```
+ */
+export const useConfirmTopics = () => {
+  const queryClient = useQueryClient()
+
+  return useMutation<ConfirmTopicsResponse, ApiError, ConfirmTopicsParams>({
+    mutationFn: (params: ConfirmTopicsParams) => confirmTopics(params),
+    onSuccess: (_, variables) => {
+      // 제안된 주제 무효화
+      queryClient.invalidateQueries({
+        queryKey: topicQueryKeys.proposedList({
+          gatheringId: variables.gatheringId,
+          meetingId: variables.meetingId,
+        }),
+      })
+      // 확정된 주제 무효화
+      queryClient.invalidateQueries({
+        queryKey: topicQueryKeys.confirmedList({
+          gatheringId: variables.gatheringId,
+          meetingId: variables.meetingId,
+        }),
+      })
+    },
+  })
+}
diff --git a/src/features/topics/topics.api.ts b/src/features/topics/topics.api.ts
index 703aad3..9459738 100644
--- a/src/features/topics/topics.api.ts
+++ b/src/features/topics/topics.api.ts
@@ -7,8 +7,10 @@ import { api } from '@/api/client'
 import { PAGE_SIZES } from '@/shared/constants'
 
 import { TOPICS_ENDPOINTS } from './topics.endpoints'
-import { getMockConfirmedTopics, getMockProposedTopics } from './topics.mock'
+import { getMockConfirmedTopics, getMockConfirmTopics, getMockProposedTopics } from './topics.mock'
 import type {
+  ConfirmTopicsParams,
+  ConfirmTopicsResponse,
   CreateTopicParams,
   CreateTopicResponse,
   DeleteTopicParams,
@@ -211,3 +213,35 @@ export const likeTopicToggle = async (params: LikeTopicParams): Promise<LikeTopi
   // 실제 API 호출 (로그인 완료 후 사용)
   return api.post<LikeTopicResponse>(TOPICS_ENDPOINTS.LIKE_TOGGLE(gatheringId, meetingId, topicId))
 }
+
+/**
+ * 주제 확정
+ *
+ * @description
+ * 선택한 주제들을 순서대로 확정합니다.
+ *
+ * @param params - 확정 파라미터
+ * @param params.gatheringId - 모임 식별자
+ * @param params.meetingId - 약속 식별자
+ * @param params.topicIds - 확정할 주제 ID 목록 (순서대로)
+ *
+ * @returns 확정된 주제 정보
+ */
+export const confirmTopics = async (
+  params: ConfirmTopicsParams
+): Promise<ConfirmTopicsResponse> => {
+  const { gatheringId, meetingId, topicIds } = params
+
+  // 🚧 임시: 로그인 기능 개발 전까지 목데이터 사용
+  // TODO: 로그인 완료 후 아래 주석을 해제하고 목데이터 로직 제거
+  if (USE_MOCK_DATA) {
+    // 실제 API 호출을 시뮬레이션하기 위한 지연
+    await new Promise((resolve) => setTimeout(resolve, 500))
+    return getMockConfirmTopics(meetingId, topicIds)
+  }
+
+  // 실제 API 호출 (로그인 완료 후 사용)
+  return api.post<ConfirmTopicsResponse>(TOPICS_ENDPOINTS.CONFIRM(gatheringId, meetingId), {
+    topicIds,
+  })
+}
diff --git a/src/features/topics/topics.endpoints.ts b/src/features/topics/topics.endpoints.ts
index 57e9232..391a01e 100644
--- a/src/features/topics/topics.endpoints.ts
+++ b/src/features/topics/topics.endpoints.ts
@@ -17,6 +17,9 @@ export const TOPICS_ENDPOINTS = {
   LIKE_TOGGLE: (gatheringId: number, meetingId: number, topicId: number) =>
     `${API_PATHS.GATHERINGS}/${gatheringId}/meetings/${meetingId}/topics/${topicId}/likes`,
 
+  // 주제 확정 (POST /api/gatherings/{gatheringId}/meetings/{meetingId}/topics/confirm)
+  CONFIRM: (gatheringId: number, meetingId: number) =>
+    `${API_PATHS.GATHERINGS}/${gatheringId}/meetings/${meetingId}/topics/confirm`,
   // 주제 제안 (POST /api/gatherings/{gatheringId}/meetings/{meetingId}/topics)
   CREATE: (gatheringId: number, meetingId: number) =>
     `${API_PATHS.GATHERINGS}/${gatheringId}/meetings/${meetingId}/topics`,
diff --git a/src/features/topics/topics.mock.ts b/src/features/topics/topics.mock.ts
index 69feca6..e535579 100644
--- a/src/features/topics/topics.mock.ts
+++ b/src/features/topics/topics.mock.ts
@@ -5,6 +5,7 @@
 
 import type {
   ConfirmedTopicItem,
+  ConfirmTopicsResponse,
   GetConfirmedTopicsResponse,
   GetProposedTopicsResponse,
   ProposedTopicItem,
@@ -435,7 +436,7 @@ export const getMockProposedTopics = (
     nextCursor,
     totalCount: cursorLikeCount === undefined ? mockProposedTopics.length : undefined,
     actions: {
-      canConfirm: false,
+      canConfirm: true,
       canSuggest: true,
     },
   }
@@ -489,3 +490,23 @@ export const getMockConfirmedTopics = (
     },
   }
 }
+
+/**
+ * 주제 확정 목데이터 반환 함수
+ *
+ * @description
+ * 실제 API 호출을 시뮬레이션하여 주제 확정 응답 목데이터를 반환합니다.
+ */
+export const getMockConfirmTopics = (
+  meetingId: number,
+  topicIds: number[]
+): ConfirmTopicsResponse => {
+  return {
+    meetingId,
+    topicStatus: 'CONFIRMED',
+    topics: topicIds.map((topicId, index) => ({
+      topicId,
+      confirmOrder: index + 1,
+    })),
+  }
+}
diff --git a/src/features/topics/topics.types.ts b/src/features/topics/topics.types.ts
index e973a70..68e8b5a 100644
--- a/src/features/topics/topics.types.ts
+++ b/src/features/topics/topics.types.ts
@@ -35,7 +35,7 @@ export type ProposedTopicItem = {
   meetingId: number
   /** 주제 제목 */
   title: string
-  /** 주제 설명 */
+  /** 주제 설명 (Todo : 없을떄 null인지 빈값인지 체크해야함)*/
   description: string
   /** 주제 타입 */
   topicType: TopicType
@@ -64,7 +64,7 @@ export type ConfirmedTopicItem = {
   topicId: number
   /** 주제 제목 */
   title: string
-  /** 주제 설명 */
+  /** 주제 설명 (Todo : 없을떄 null인지 빈값인지 체크해야함)*/
   description: string
   /** 주제 타입 */
   topicType: TopicType
@@ -199,6 +199,33 @@ export type LikeTopicResponse = {
   newCount: number
 }
 
+/**
+ * 주제 확정 요청 파라미터
+ */
+export type ConfirmTopicsParams = {
+  /** 모임 식별자 */
+  gatheringId: number
+  /** 약속 식별자 */
+  meetingId: number
+  /** 확정할 주제 ID 목록 (순서대로) */
+  topicIds: number[]
+}
+
+/**
+ * 주제 확정 응답
+ */
+export type ConfirmTopicsResponse = {
+  /** 약속 식별자 */
+  meetingId: number
+  /** 주제 상태 */
+  topicStatus: TopicStatus
+  /** 확정된 주제 목록 */
+  topics: Array<{
+    topicId: number
+    confirmOrder: number
+  }>
+}
+
 /**
  * 주제 제안 요청 파라미터
  */
diff --git a/src/pages/Meetings/MeetingDetailPage.tsx b/src/pages/Meetings/MeetingDetailPage.tsx
index 7686f4f..cbef6d5 100644
--- a/src/pages/Meetings/MeetingDetailPage.tsx
+++ b/src/pages/Meetings/MeetingDetailPage.tsx
@@ -15,6 +15,7 @@ import type {
 } from '@/features/topics'
 import {
   ConfirmedTopicList,
+  ConfirmTopicModal,
   ProposedTopicList,
   TopicHeader,
   useConfirmedTopics,
@@ -26,6 +27,7 @@ export default function MeetingDetailPage() {
   const { gatheringId, meetingId } = useParams<{ gatheringId: string; meetingId: string }>()
 
   const [activeTab, setActiveTab] = useState<TopicStatus>('PROPOSED')
+  const [isConfirmTopicOpen, setIsConfirmTopicOpen] = useState(false)
 
   const { data: meeting, isLoading, error } = useMeetingDetail(Number(meetingId))
 
@@ -109,7 +111,7 @@ export default function MeetingDetailPage() {
         </div>
         {/* 약속 로딩 적용 */}
 
-        <div className="flex flex-col flex-1 gap-base">
+        <div className="flex flex-col flex-1 gap-base pb-base">
           <p className="text-black typo-heading3">주제</p>
 
           <Tabs
@@ -147,6 +149,8 @@ export default function MeetingDetailPage() {
                     confirmedTopic={meeting?.confirmedTopicExpand ?? false}
                     actions={proposedTopicsInfiniteData.pages[0].actions}
                     confirmedTopicDate={meeting?.confirmedTopicDate ?? null}
+                    proposedTopicsCount={proposedTopicsInfiniteData.pages[0].totalCount ?? 0}
+                    onOpenChange={setIsConfirmTopicOpen}
                   />
                   <ProposedTopicList
                     topics={proposedTopicsInfiniteData.pages.flatMap(
@@ -191,6 +195,14 @@ export default function MeetingDetailPage() {
           </Tabs>
         </div>
       </div>
+      {isConfirmTopicOpen && (
+        <ConfirmTopicModal
+          open={isConfirmTopicOpen}
+          onOpenChange={setIsConfirmTopicOpen}
+          gatheringId={Number(gatheringId)}
+          meetingId={Number(meetingId)}
+        />
+      )}
     </>
   )
 }
diff --git a/src/shared/ui/NumberedCheckbox.tsx b/src/shared/ui/NumberedCheckbox.tsx
index 4f288ae..b0c56a8 100644
--- a/src/shared/ui/NumberedCheckbox.tsx
+++ b/src/shared/ui/NumberedCheckbox.tsx
@@ -1,4 +1,4 @@
-import { createContext, type ReactNode, useContext } from 'react'
+import { createContext, forwardRef, type ReactNode, useContext } from 'react'
 
 import { cn } from '@/shared/lib/utils'
 
@@ -68,38 +68,41 @@ export interface NumberedCheckboxProps {
   disabled?: boolean
 }
 
-function NumberedCheckbox({ id, className, children, disabled = false }: NumberedCheckboxProps) {
-  const { selected, toggle } = useNumberedCheckboxContext()
+const NumberedCheckbox = forwardRef<HTMLButtonElement, NumberedCheckboxProps>(
+  function NumberedCheckbox({ id, className, children, disabled = false }, ref) {
+    const { selected, toggle } = useNumberedCheckboxContext()
 
-  const index = selected.indexOf(id)
-  const isChecked = index !== -1
-  const displayNumber = isChecked ? index + 1 : undefined
+    const index = selected.indexOf(id)
+    const isChecked = index !== -1
+    const displayNumber = isChecked ? index + 1 : undefined
 
-  return (
-    <div className="inline-flex items-center gap-2 align-middle">
-      <button
-        type="button"
-        role="checkbox"
-        aria-checked={isChecked}
-        aria-disabled={disabled}
-        data-slot="numbered-checkbox"
-        data-state={isChecked ? 'checked' : 'unchecked'}
-        onClick={() => !disabled && toggle(id)}
-        disabled={disabled}
-        className={cn(
-          'inline-flex items-center justify-center size-8 shrink-0 rounded-medium border transition-colors align-middle',
-          disabled ? 'invisible pointer-events-none' : 'cursor-pointer',
-          isChecked ? 'bg-primary-200 border-primary-200' : 'bg-transparent border-grey-300',
-          className
-        )}
-      >
-        <span className={cn('typo-body3 leading-none', isChecked ? 'text-black' : 'invisible')}>
-          {displayNumber ?? 0}
-        </span>
-      </button>
-      {children && <span className="align-middle">{children}</span>}
-    </div>
-  )
-}
+    return (
+      <div className="inline-flex items-center gap-2 align-middle">
+        <button
+          ref={ref}
+          type="button"
+          role="checkbox"
+          aria-checked={isChecked}
+          aria-disabled={disabled}
+          data-slot="numbered-checkbox"
+          data-state={isChecked ? 'checked' : 'unchecked'}
+          onClick={() => !disabled && toggle(id)}
+          disabled={disabled}
+          className={cn(
+            'inline-flex items-center justify-center size-8 shrink-0 rounded-medium border transition-colors align-middle',
+            disabled ? 'invisible pointer-events-none' : 'cursor-pointer',
+            isChecked ? 'bg-primary-200 border-primary-200' : 'bg-transparent border-grey-300',
+            className
+          )}
+        >
+          <span className={cn('typo-body3 leading-none', isChecked ? 'text-black' : 'invisible')}>
+            {displayNumber ?? 0}
+          </span>
+        </button>
+        {children && <span className="align-middle">{children}</span>}
+      </div>
+    )
+  }
+)
 
 export { NumberedCheckbox, NumberedCheckboxGroup }