diff --git a/src/main/java/jp/openstandia/connector/github/GitHubClient.java b/src/main/java/jp/openstandia/connector/github/GitHubClient.java
index eb61a13..ed1f363 100644
--- a/src/main/java/jp/openstandia/connector/github/GitHubClient.java
+++ b/src/main/java/jp/openstandia/connector/github/GitHubClient.java
@@ -24,6 +24,7 @@
 import org.kohsuke.github.SCIMUser;
 
 import java.util.Collection;
+import java.util.List;
 import java.util.Set;
 
 /**
@@ -50,6 +51,8 @@ public interface GitHubClient {
 
     void getUser(GitHubSchema schema, Name name, ResultsHandler handler, OperationOptions options, Set<String> attributesToGet, boolean allowPartialAttributeValues, int queryPageSize);
 
+    List<String> getTeamIdsByUsername(String userLogin, int pageSize);
+
     boolean isOrganizationMember(String userLogin);
 
     void assignOrganizationRole(String userLogin, String organizationRole);
diff --git a/src/main/java/jp/openstandia/connector/github/GitHubUserHandler.java b/src/main/java/jp/openstandia/connector/github/GitHubUserHandler.java
index 73da3f6..b167f53 100644
--- a/src/main/java/jp/openstandia/connector/github/GitHubUserHandler.java
+++ b/src/main/java/jp/openstandia/connector/github/GitHubUserHandler.java
@@ -22,6 +22,7 @@
 import org.kohsuke.github.SCIMUser;
 
 import java.util.HashSet;
+import java.util.List;
 import java.util.Set;
 import java.util.stream.Collectors;
 
@@ -305,6 +306,16 @@ private String resolveUserLogin(Uid oldUid, String newNameValue) {
 
     @Override
     public void delete(Uid uid, OperationOptions options) {
+        String userLogin = getUserLogin(uid);
+        if (!userLogin.equals(UNKNOWN_USER_NAME)) {
+            // Fix https://github.com/openstandia/connector-github/issues/6
+            // GitHub maintains the user's team association after deletion
+            // So, we need to remove the association first
+            List<String> teamIds = client.getTeamIdsByUsername(userLogin, configuration.getQueryPageSize());
+            client.unassignTeams(userLogin, teamIds);
+        }
+
+        // Finally, do delete the user
         client.deleteUser(schema, uid, options);
     }
 
diff --git a/src/main/java/jp/openstandia/connector/github/rest/GitHubRESTClient.java b/src/main/java/jp/openstandia/connector/github/rest/GitHubRESTClient.java
index 5152377..f6698a9 100644
--- a/src/main/java/jp/openstandia/connector/github/rest/GitHubRESTClient.java
+++ b/src/main/java/jp/openstandia/connector/github/rest/GitHubRESTClient.java
@@ -334,6 +334,17 @@ public void getUser(GitHubSchema schema, Name name, ResultsHandler handler, Oper
         });
     }
 
+    @Override
+    public List<String> getTeamIdsByUsername(String userLogin, int pageSize) {
+        return withAuth(() -> {
+            return orgApiClient.listTeams(userLogin, pageSize)
+                    .toList().stream()
+                    .filter(t -> t.node.members.totalCount == 1)
+                    .map(GitHubUtils::toTeamUid)
+                    .collect(Collectors.toList());
+        });
+    }
+
     private ConnectorObject toConnectorObject(GitHubSchema schema, String queryLogin, SCIMUser user,
                                               Set<String> attributesToGet, boolean allowPartialAttributeValues, int queryPageSize) {
 
diff --git a/src/test/java/jp/openstandia/connector/github/testutil/MockClient.java b/src/test/java/jp/openstandia/connector/github/testutil/MockClient.java
index 06fd2bc..3a09dd8 100644
--- a/src/test/java/jp/openstandia/connector/github/testutil/MockClient.java
+++ b/src/test/java/jp/openstandia/connector/github/testutil/MockClient.java
@@ -11,6 +11,7 @@
 import org.kohsuke.github.SCIMUser;
 
 import java.util.Collection;
+import java.util.List;
 import java.util.Set;
 
 public class MockClient implements GitHubClient {
@@ -67,6 +68,11 @@ public void getUser(GitHubSchema schema, Name name, ResultsHandler handler, Oper
 
     }
 
+    @Override
+    public List<String> getTeamIdsByUsername(String userLogin, int pageSize) {
+        return null;
+    }
+
     @Override
     public boolean isOrganizationMember(String userLogin) {
         return false;