diff --git a/src/test/kotlin/roomescape/reservation/ReservationApiTest.kt b/src/test/kotlin/roomescape/reservation/ReservationApiTest.kt
index 626b54b5..ca8d073b 100644
--- a/src/test/kotlin/roomescape/reservation/ReservationApiTest.kt
+++ b/src/test/kotlin/roomescape/reservation/ReservationApiTest.kt
@@ -6,7 +6,10 @@ import org.springframework.data.repository.findByIdOrNull
 import org.springframework.http.HttpMethod
 import org.springframework.http.HttpStatus
 import roomescape.auth.exception.AuthErrorCode
+import roomescape.common.config.next
 import roomescape.common.exception.CommonErrorCode
+import roomescape.common.util.DateUtils
+import roomescape.member.infrastructure.persistence.UserEntity
 import roomescape.payment.exception.PaymentErrorCode
 import roomescape.payment.infrastructure.common.BankCode
 import roomescape.payment.infrastructure.common.CardIssuerCode
@@ -17,18 +20,22 @@ import roomescape.reservation.infrastructure.persistence.CanceledReservationRepo
 import roomescape.reservation.infrastructure.persistence.ReservationEntity
 import roomescape.reservation.infrastructure.persistence.ReservationRepository
 import roomescape.reservation.infrastructure.persistence.ReservationStatus
+import roomescape.reservation.web.MostReservedThemeIdListResponse
 import roomescape.reservation.web.ReservationCancelRequest
 import roomescape.schedule.infrastructure.persistence.ScheduleEntity
 import roomescape.schedule.infrastructure.persistence.ScheduleRepository
 import roomescape.schedule.infrastructure.persistence.ScheduleStatus
-import roomescape.theme.infrastructure.persistence.ThemeEntity
 import roomescape.supports.*
+import roomescape.theme.infrastructure.persistence.ThemeEntity
+import roomescape.theme.infrastructure.persistence.ThemeRepository
+import roomescape.theme.web.toEntity
 import java.time.LocalDate
 import java.time.LocalTime
 
 class ReservationApiTest(
     private val reservationRepository: ReservationRepository,
     private val canceledReservationRepository: CanceledReservationRepository,
+    private val themeRepository: ThemeRepository,
     private val scheduleRepository: ScheduleRepository,
     private val paymentDetailRepository: PaymentDetailRepository,
 ) : FunSpecSpringbootTest() {
@@ -299,7 +306,8 @@ class ReservationApiTest(
                     reserverToken = authUtil.defaultUserLogin(),
                 )
 
-                val otherUserToken = authUtil.userLogin(UserFixture.createUser(email = "test@test.com", phone="01011111111"))
+                val otherUserToken =
+                    authUtil.userLogin(UserFixture.createUser(email = "test@test.com", phone = "01011111111"))
 
                 runExceptionTest(
                     token = otherUserToken,
@@ -602,6 +610,24 @@ class ReservationApiTest(
                 )
             }
         }
+
+        context("가장 많이 예약된 테마 ID를 조회한다.") {
+            test("정상 응답") {
+                val expectedResult: MostReservedThemeIdListResponse = initializeForPopularThemeTest()
+
+                runTest(
+                    on = {
+                        get("/reservations/popular-themes?count=10")
+                    },
+                    expect = {
+                        statusCode(HttpStatus.OK.value())
+                    }
+                ).also {
+                    val result: List<Long> = it.extract().path("data.themeIds")
+                    result shouldBe expectedResult.themeIds
+                }
+            }
+        }
     }
 
     fun runDetailRetrieveTest(
@@ -621,4 +647,92 @@ class ReservationApiTest(
             it.extract().path<Long>("data.user.id") shouldBe reservation.userId
         }.extract().path("data.payment")
     }
+
+    private fun initializeForPopularThemeTest(): MostReservedThemeIdListResponse {
+        val user: UserEntity = authUtil.defaultUser()
+
+        val themeIds: List<Long> = (1..5).map {
+            themeRepository.save(
+                ThemeFixture.createRequest.copy(name = "theme-$it").toEntity(id = tsidFactory.next())
+            ).id
+        }
+
+        // 첫 번째 테마: 유효한 2개 예약
+        (1L..2L).forEach {
+            createScheduleAndReservation(
+                date = DateUtils.getSundayOfPreviousWeek(LocalDate.now()).plusDays(it),
+                themeId = themeIds[0],
+                userId = user.id,
+            )
+        }
+
+        // 두 번째 테마: 유효한 1개 예약
+        createScheduleAndReservation(
+            date = DateUtils.getSundayOfPreviousWeek(LocalDate.now()),
+            themeId = themeIds[1],
+            userId = user.id,
+        )
+
+        // 세 번째 테마: 유효한 3개 예약
+        (1L..3L).forEach {
+            createScheduleAndReservation(
+                date = DateUtils.getSundayOfPreviousWeek(LocalDate.now()).plusDays(it),
+                themeId = themeIds[2],
+                userId = user.id,
+            )
+        }
+
+        // 네 번째 테마: Pending 상태인 3개 예약 -> 집계되지 않음.
+        (1L..3L).forEach {
+            createScheduleAndReservation(
+                date = DateUtils.getSundayOfPreviousWeek(LocalDate.now()).plusDays(it),
+                themeId = themeIds[3],
+                userId = user.id,
+                isPending = true
+            )
+        }
+
+        // 다섯 번째 테마: 이번주의 확정 예약 -> 집계되지 않음.
+        (1L..3L).forEach { i ->
+            val thisMonday = DateUtils.getSundayOfPreviousWeek(LocalDate.now()).plusDays(8)
+            createScheduleAndReservation(
+                date = thisMonday.plusDays(i),
+                themeId = themeIds[4],
+                userId = user.id,
+            )
+        }
+
+        // 조회 예상 결과: 세번째, 첫번째, 두번째 테마 순서
+        return MostReservedThemeIdListResponse(listOf(themeIds[2], themeIds[0], themeIds[1]))
+    }
+
+    private fun createScheduleAndReservation(
+        date: LocalDate,
+        themeId: Long,
+        userId: Long,
+        isPending: Boolean = false
+    ) {
+        val schedule = ScheduleEntity(
+            id = tsidFactory.next(),
+            date = date,
+            time = LocalTime.now(),
+            themeId = themeId,
+            status = if (isPending) ScheduleStatus.HOLD else ScheduleStatus.RESERVED
+        ).also {
+            scheduleRepository.save(it)
+        }
+
+        ReservationEntity(
+            id = tsidFactory.next(),
+            userId = userId,
+            scheduleId = schedule.id,
+            reserverName = "이상돌",
+            reserverContact = "01012345678",
+            participantCount = 4,
+            requirement = "잘부탁드려요!",
+            status = if (isPending) ReservationStatus.PENDING else ReservationStatus.CONFIRMED,
+        ).also {
+            reservationRepository.save(it)
+        }
+    }
 }