diff --git a/docs/plan/#19-review-update/checklist.md b/docs/plan/#19-review-update/checklist.md
new file mode 100644
index 0000000..624eb3b
--- /dev/null
+++ b/docs/plan/#19-review-update/checklist.md
@@ -0,0 +1,12 @@
+# Review 수정 Mutation 검증 체크리스트
+
+## 필수 항목
+- [x] 아키텍처 원칙 준수 (docs/architecture.md 기준)
+- [x] 레이어 의존성 규칙 위반 없음
+- [x] 테스트 코드 작성 완료 (Domain, Application 필수)
+- [x] 모든 테스트 통과
+- [x] 기존 테스트 깨지지 않음
+
+## 선택 항목 (해당 시)
+- [x] 본인 회고만 수정 가능 (소유권 검증)
+- [x] DGS Codegen 타입 자동 생성 확인
diff --git a/docs/plan/#19-review-update/plan.md b/docs/plan/#19-review-update/plan.md
new file mode 100644
index 0000000..65c61e7
--- /dev/null
+++ b/docs/plan/#19-review-update/plan.md
@@ -0,0 +1,13 @@
+# Review 수정 Mutation 추가 계획
+
+> Issue: #19
+
+## 단계
+
+- [x] 1단계: Domain — ReviewCommand.Update 추가 + Review 도메인 테스트
+- [x] 2단계: Domain — ReviewRepository에 update 메서드 추가
+- [x] 3단계: Application — ReviewService.update 구현 (소유권 검증 포함) + 테스트
+- [x] 4단계: GraphQL 스키마 — UpdateReviewInput, updateReview Mutation 추가
+- [x] 5단계: Infrastructure — ExposedReviewRepository.update 구현
+- [x] 6단계: Presentation — ReviewDataFetcher.updateReview 구현
+- [x] 7단계: 빌드 및 전체 테스트 통과 확인
diff --git a/src/main/kotlin/kr/io/team/loop/review/application/service/ReviewService.kt b/src/main/kotlin/kr/io/team/loop/review/application/service/ReviewService.kt
index 0a4b1db..a688fd3 100644
--- a/src/main/kotlin/kr/io/team/loop/review/application/service/ReviewService.kt
+++ b/src/main/kotlin/kr/io/team/loop/review/application/service/ReviewService.kt
@@ -41,6 +41,20 @@ class ReviewService(
             throw DuplicateEntityException("Review already exists for this period")
         }
 
+    @Transactional
+    fun update(
+        command: ReviewCommand.Update,
+        memberId: MemberId,
+    ): Review {
+        val review =
+            reviewRepository.findById(command.reviewId)
+                ?: throw EntityNotFoundException("Review not found: ${command.reviewId.value}")
+        if (!review.isOwnedBy(memberId)) {
+            throw AccessDeniedException("Cannot update other member's review")
+        }
+        return reviewRepository.update(command)
+    }
+
     @Transactional(readOnly = true)
     fun findAll(query: ReviewQuery): List<Review> {
         val reviews = reviewRepository.findAll(query.copy(stepType = null))
diff --git a/src/main/kotlin/kr/io/team/loop/review/domain/model/Review.kt b/src/main/kotlin/kr/io/team/loop/review/domain/model/Review.kt
index 4e834ac..c5d5bb0 100644
--- a/src/main/kotlin/kr/io/team/loop/review/domain/model/Review.kt
+++ b/src/main/kotlin/kr/io/team/loop/review/domain/model/Review.kt
@@ -18,4 +18,6 @@ data class Review(
     fun isOwnedBy(memberId: MemberId): Boolean = this.memberId == memberId
 
     fun containsStepType(stepType: StepType): Boolean = steps.any { it.type == stepType }
+
+    fun withUpdatedSteps(newSteps: List<ReviewStep>): Review = copy(steps = newSteps)
 }
diff --git a/src/main/kotlin/kr/io/team/loop/review/domain/model/ReviewCommand.kt b/src/main/kotlin/kr/io/team/loop/review/domain/model/ReviewCommand.kt
index 30f5bc2..4bbf04f 100644
--- a/src/main/kotlin/kr/io/team/loop/review/domain/model/ReviewCommand.kt
+++ b/src/main/kotlin/kr/io/team/loop/review/domain/model/ReviewCommand.kt
@@ -10,6 +10,11 @@ sealed interface ReviewCommand {
         val date: LocalDate,
     ) : ReviewCommand
 
+    data class Update(
+        val reviewId: ReviewId,
+        val steps: List<ReviewStep>,
+    ) : ReviewCommand
+
     data class Delete(
         val reviewId: ReviewId,
     ) : ReviewCommand
diff --git a/src/main/kotlin/kr/io/team/loop/review/domain/repository/ReviewRepository.kt b/src/main/kotlin/kr/io/team/loop/review/domain/repository/ReviewRepository.kt
index 4e9bae6..02976b8 100644
--- a/src/main/kotlin/kr/io/team/loop/review/domain/repository/ReviewRepository.kt
+++ b/src/main/kotlin/kr/io/team/loop/review/domain/repository/ReviewRepository.kt
@@ -8,6 +8,8 @@ import kr.io.team.loop.review.domain.model.ReviewQuery
 interface ReviewRepository {
     fun save(command: ReviewCommand.Create): Review
 
+    fun update(command: ReviewCommand.Update): Review
+
     fun delete(command: ReviewCommand.Delete)
 
     fun findAll(query: ReviewQuery): List<Review>
diff --git a/src/main/kotlin/kr/io/team/loop/review/infrastructure/persistence/ExposedReviewRepository.kt b/src/main/kotlin/kr/io/team/loop/review/infrastructure/persistence/ExposedReviewRepository.kt
index a342287..c175da3 100644
--- a/src/main/kotlin/kr/io/team/loop/review/infrastructure/persistence/ExposedReviewRepository.kt
+++ b/src/main/kotlin/kr/io/team/loop/review/infrastructure/persistence/ExposedReviewRepository.kt
@@ -21,6 +21,7 @@ import org.jetbrains.exposed.v1.core.lessEq
 import org.jetbrains.exposed.v1.jdbc.deleteWhere
 import org.jetbrains.exposed.v1.jdbc.insert
 import org.jetbrains.exposed.v1.jdbc.selectAll
+import org.jetbrains.exposed.v1.jdbc.update
 import org.springframework.stereotype.Repository
 import java.time.OffsetDateTime
 
@@ -58,6 +59,18 @@ class ExposedReviewRepository : ReviewRepository {
         )
     }
 
+    override fun update(command: ReviewCommand.Update): Review {
+        val now = OffsetDateTime.now()
+        val stepsJson = command.steps.map { StepJson(type = it.type.name, content = it.content) }
+
+        ReviewTable.update({ ReviewTable.reviewId eq command.reviewId.value }) {
+            it[steps] = stepsJson
+            it[updatedAt] = now
+        }
+
+        return findById(command.reviewId)!!
+    }
+
     override fun findAll(query: ReviewQuery): List<Review> {
         var condition: Op<Boolean> = Op.TRUE
         query.memberId?.let { condition = condition and (ReviewTable.memberId eq it.value) }
diff --git a/src/main/kotlin/kr/io/team/loop/review/presentation/datafetcher/ReviewDataFetcher.kt b/src/main/kotlin/kr/io/team/loop/review/presentation/datafetcher/ReviewDataFetcher.kt
index c0baa55..e478f3a 100644
--- a/src/main/kotlin/kr/io/team/loop/review/presentation/datafetcher/ReviewDataFetcher.kt
+++ b/src/main/kotlin/kr/io/team/loop/review/presentation/datafetcher/ReviewDataFetcher.kt
@@ -10,6 +10,7 @@ import kotlinx.datetime.toLocalDateTime
 import kr.io.team.loop.codegen.types.CreateReviewInput
 import kr.io.team.loop.codegen.types.ReviewFilter
 import kr.io.team.loop.codegen.types.ReviewStepOutput
+import kr.io.team.loop.codegen.types.UpdateReviewInput
 import kr.io.team.loop.common.config.Authorize
 import kr.io.team.loop.common.domain.MemberId
 import kr.io.team.loop.review.application.service.ReviewService
@@ -83,6 +84,25 @@ class ReviewDataFetcher(
         return reviewService.create(command).toGraphql()
     }
 
+    @DgsMutation
+    fun updateReview(
+        @InputArgument input: UpdateReviewInput,
+        @Authorize memberId: Long,
+    ): ReviewGraphql {
+        val command =
+            ReviewCommand.Update(
+                reviewId = ReviewId(input.id.toLong()),
+                steps =
+                    input.steps.map { step ->
+                        ReviewStep(
+                            type = StepTypeDomain.valueOf(step.type.name),
+                            content = step.content,
+                        )
+                    },
+            )
+        return reviewService.update(command, MemberId(memberId)).toGraphql()
+    }
+
     @DgsMutation
     fun deleteReview(
         @InputArgument id: String,
diff --git a/src/main/resources/schema/review.graphqls b/src/main/resources/schema/review.graphqls
index 6387a35..48e69a3 100644
--- a/src/main/resources/schema/review.graphqls
+++ b/src/main/resources/schema/review.graphqls
@@ -16,6 +16,12 @@ extend type Mutation {
         input: CreateReviewInput!
     ): Review!
 
+    "기존 KPT 회고의 단계별 내용을 수정한다. 본인 회고만 수정 가능. (인증 필수)"
+    updateReview(
+        "수정할 회고 정보"
+        input: UpdateReviewInput!
+    ): Review!
+
     "회고를 삭제한다. (본인 회고만)"
     deleteReview(
         "삭제할 회고 ID"
@@ -95,6 +101,14 @@ input CreateReviewInput {
     date: String!
 }
 
+"""회고 수정 입력"""
+input UpdateReviewInput {
+    "수정할 회고 ID"
+    id: ID!
+    "수정할 회고 단계 목록 (최소 1개)"
+    steps: [ReviewStepInput!]!
+}
+
 """회고 단계 입력"""
 input ReviewStepInput {
     "단계 유형"
diff --git a/src/test/kotlin/kr/io/team/loop/review/application/service/ReviewServiceTest.kt b/src/test/kotlin/kr/io/team/loop/review/application/service/ReviewServiceTest.kt
index 11a5c7c..b7ca501 100644
--- a/src/test/kotlin/kr/io/team/loop/review/application/service/ReviewServiceTest.kt
+++ b/src/test/kotlin/kr/io/team/loop/review/application/service/ReviewServiceTest.kt
@@ -95,6 +95,53 @@ class ReviewServiceTest :
             }
         }
 
+        Given("회고 수정 시") {
+            val updateCommand =
+                ReviewCommand.Update(
+                    reviewId = ReviewId(1L),
+                    steps =
+                        listOf(
+                            ReviewStep(type = StepType.KEEP, content = "수정된 좋은 점"),
+                            ReviewStep(type = StepType.TRY, content = "수정된 다짐"),
+                        ),
+                )
+
+            When("본인 회고를 수정하면") {
+                every { reviewRepository.findById(ReviewId(1L)) } returns savedReview
+                val updatedReview = savedReview.withUpdatedSteps(updateCommand.steps)
+                every { reviewRepository.update(updateCommand) } returns updatedReview
+
+                val result = reviewService.update(updateCommand, memberId)
+
+                Then("수정된 회고를 반환한다") {
+                    result.steps shouldHaveSize 2
+                    result.steps[0].content shouldBe "수정된 좋은 점"
+                    result.steps[1].content shouldBe "수정된 다짐"
+                }
+            }
+
+            When("존재하지 않는 회고를 수정하면") {
+                every { reviewRepository.findById(ReviewId(1L)) } returns null
+
+                Then("EntityNotFoundException이 발생한다") {
+                    shouldThrow<EntityNotFoundException> {
+                        reviewService.update(updateCommand, memberId)
+                    }
+                }
+            }
+
+            When("다른 사용자의 회고를 수정하면") {
+                every { reviewRepository.findById(ReviewId(1L)) } returns savedReview
+                val otherMemberId = MemberId(99L)
+
+                Then("AccessDeniedException이 발생한다") {
+                    shouldThrow<AccessDeniedException> {
+                        reviewService.update(updateCommand, otherMemberId)
+                    }
+                }
+            }
+        }
+
         Given("회고 목록 조회 시") {
             When("해당 사용자의 회고가 있으면") {
                 val query = ReviewQuery(memberId = memberId)
diff --git a/src/test/kotlin/kr/io/team/loop/review/domain/model/ReviewTest.kt b/src/test/kotlin/kr/io/team/loop/review/domain/model/ReviewTest.kt
index ee304ad..8211de8 100644
--- a/src/test/kotlin/kr/io/team/loop/review/domain/model/ReviewTest.kt
+++ b/src/test/kotlin/kr/io/team/loop/review/domain/model/ReviewTest.kt
@@ -44,6 +44,24 @@ class ReviewTest :
             }
         }
 
+        Given("Review 수정 시") {
+            When("새로운 steps로 수정하면") {
+                val newSteps =
+                    listOf(
+                        ReviewStep(type = StepType.KEEP, content = "수정된 좋은 점"),
+                        ReviewStep(type = StepType.TRY, content = "수정된 다짐"),
+                    )
+                val updated = review.withUpdatedSteps(newSteps)
+
+                Then("steps가 변경된 새 Review를 반환한다") {
+                    updated.steps shouldBe newSteps
+                    updated.id shouldBe review.id
+                    updated.memberId shouldBe review.memberId
+                    updated.startDate shouldBe review.startDate
+                }
+            }
+        }
+
         Given("Review에 특정 StepType 포함 여부 확인 시") {
             When("KEEP이 포함되어 있으면") {
                 Then("true를 반환한다") {