diff --git a/src/main/kotlin/org/gitanimals/guild/app/LeaveGuildFacade.kt b/src/main/kotlin/org/gitanimals/guild/app/LeaveGuildFacade.kt
new file mode 100644
index 0000000..cc0a2ce
--- /dev/null
+++ b/src/main/kotlin/org/gitanimals/guild/app/LeaveGuildFacade.kt
@@ -0,0 +1,17 @@
+package org.gitanimals.guild.app
+
+import org.gitanimals.guild.domain.GuildService
+import org.springframework.stereotype.Component
+
+@Component
+class LeaveGuildFacade(
+    private val identityApi: IdentityApi,
+    private val guildService: GuildService,
+) {
+
+    fun leave(token: String, guildId: Long) {
+        val user = identityApi.getUserByToken(token)
+
+        guildService.leave(guildId, user.id.toLong())
+    }
+}
diff --git a/src/main/kotlin/org/gitanimals/guild/controller/GuildController.kt b/src/main/kotlin/org/gitanimals/guild/controller/GuildController.kt
index 444fb4d..383e3c5 100644
--- a/src/main/kotlin/org/gitanimals/guild/controller/GuildController.kt
+++ b/src/main/kotlin/org/gitanimals/guild/controller/GuildController.kt
@@ -26,6 +26,7 @@ class GuildController(
     private val joinedGuildFacade: GetJoinedGuildFacade,
     private val searchGuildFacade: SearchGuildFacade,
     private val changeMainPersonaFacade: ChangeMainPersonaFacade,
+    private val leaveGuildFacade: LeaveGuildFacade,
 ) {
 
     @ResponseStatus(HttpStatus.OK)
@@ -128,4 +129,10 @@ class GuildController(
         guildId = guildId,
         personaId = personaId,
     )
+
+    @DeleteMapping("/guilds/{guildId}/leave")
+    fun leaveGuild(
+        @RequestHeader(HttpHeaders.AUTHORIZATION) token: String,
+        @PathVariable("guildId") guildId: Long,
+    ) = leaveGuildFacade.leave(token, guildId)
 }
diff --git a/src/main/kotlin/org/gitanimals/guild/domain/Guild.kt b/src/main/kotlin/org/gitanimals/guild/domain/Guild.kt
index ecd18d8..bc907a1 100644
--- a/src/main/kotlin/org/gitanimals/guild/domain/Guild.kt
+++ b/src/main/kotlin/org/gitanimals/guild/domain/Guild.kt
@@ -202,6 +202,14 @@ class Guild(
         }
     }
 
+    fun leave(userId: Long) {
+        require(userId != leader.userId) {
+            "Leader cannot leave guild guildId: \"$id\", userId: \"$userId\""
+        }
+
+        members.removeIf { it.userId == userId }
+    }
+
     companion object {
 
         fun create(
diff --git a/src/main/kotlin/org/gitanimals/guild/domain/GuildService.kt b/src/main/kotlin/org/gitanimals/guild/domain/GuildService.kt
index d0476ec..66aae0e 100644
--- a/src/main/kotlin/org/gitanimals/guild/domain/GuildService.kt
+++ b/src/main/kotlin/org/gitanimals/guild/domain/GuildService.kt
@@ -6,6 +6,8 @@ import org.hibernate.Hibernate
 import org.springframework.data.domain.Page
 import org.springframework.data.domain.Pageable
 import org.springframework.data.repository.findByIdOrNull
+import org.springframework.orm.ObjectOptimisticLockingFailureException
+import org.springframework.retry.annotation.Retryable
 import org.springframework.stereotype.Service
 import org.springframework.transaction.annotation.Transactional
 
@@ -43,6 +45,7 @@ class GuildService(
     }
 
     @Transactional
+    @Retryable(ObjectOptimisticLockingFailureException::class)
     fun joinGuild(
         guildId: Long,
         memberUserId: Long,
@@ -63,6 +66,7 @@ class GuildService(
     }
 
     @Transactional
+    @Retryable(ObjectOptimisticLockingFailureException::class)
     fun acceptJoin(acceptorId: Long, guildId: Long, acceptUserId: Long) {
         val guild = guildRepository.findGuildByIdAndLeaderId(guildId, acceptorId)
             ?: throw IllegalArgumentException("Cannot accept join cause your not a leader.")
@@ -71,6 +75,7 @@ class GuildService(
     }
 
     @Transactional
+    @Retryable(ObjectOptimisticLockingFailureException::class)
     fun denyJoin(denierId: Long, guildId: Long, denyUserId: Long) {
         val guild = guildRepository.findGuildByIdAndLeaderId(guildId, denierId)
             ?: throw IllegalArgumentException("Cannot deny join cause your not a leader.")
@@ -79,6 +84,7 @@ class GuildService(
     }
 
     @Transactional
+    @Retryable(ObjectOptimisticLockingFailureException::class)
     fun kickMember(kickerId: Long, guildId: Long, kickUserId: Long) {
         val guild = guildRepository.findGuildByIdAndLeaderId(guildId, kickerId)
             ?: throw IllegalArgumentException("Cannot kick member cause your not a leader.")
@@ -87,6 +93,7 @@ class GuildService(
     }
 
     @Transactional
+    @Retryable(ObjectOptimisticLockingFailureException::class)
     fun changeGuild(changeRequesterId: Long, guildId: Long, request: ChangeGuildRequest) {
         val guild = guildRepository.findGuildByIdAndLeaderId(guildId, changeRequesterId)
             ?: throw IllegalArgumentException("Cannot kick member cause your not a leader.")
@@ -95,12 +102,21 @@ class GuildService(
     }
 
     @Transactional
+    @Retryable(ObjectOptimisticLockingFailureException::class)
     fun changeMainPersona(guildId: Long, userId: Long, personaId: Long, personaType: String) {
         val guild = getGuildById(guildId)
 
         guild.changeMainPersona(userId, personaId, personaType)
     }
 
+    @Transactional
+    @Retryable(ObjectOptimisticLockingFailureException::class)
+    fun leave(guildId: Long, userId: Long) {
+        val guild = getGuildById(guildId)
+
+        guild.leave(userId)
+    }
+
     fun getGuildById(id: Long, vararg lazyLoading: (Guild) -> Unit): Guild {
         val guild = guildRepository.findByIdOrNull(id)
             ?: throw IllegalArgumentException("Cannot fint guild by id \"$id\"")
@@ -110,6 +126,7 @@ class GuildService(
     }
 
     @Transactional
+    @Retryable(ObjectOptimisticLockingFailureException::class)
     fun updateContribution(username: String, contributions: Long) {
         val guilds = guildRepository.findAllGuildByUsernameWithMembers(username)
 
@@ -138,6 +155,7 @@ class GuildService(
     }
 
     @Transactional
+    @Retryable(ObjectOptimisticLockingFailureException::class)
     fun deletePersonaSync(
         userId: Long,
         deletedPersonaId: Long,