diff --git a/tools/syn2mas/src/migrate.mts b/tools/syn2mas/src/migrate.mts
index f78b9c8e6..93208054f 100644
--- a/tools/syn2mas/src/migrate.mts
+++ b/tools/syn2mas/src/migrate.mts
@@ -200,7 +200,11 @@ export async function migrate(): Promise<void> {
     );
   }
 
-  const synapseUsers = await synapse.select("*").from<SUser>("users");
+  // Get all Synapse users, except appservice owned users who don't need to be migrated
+  const synapseUsers = await synapse
+    .select("*")
+    .from<SUser>("users")
+    .whereNull("appservice_id");
   log.info(`Found ${synapseUsers.length} users in Synapse`);
   for (const user of synapseUsers) {
     const localpart = user.name.split(":")[0].substring(1);
diff --git a/tools/syn2mas/src/types/SUser.d.ts b/tools/syn2mas/src/types/SUser.d.ts
index c597d449d..404d7e5d9 100644
--- a/tools/syn2mas/src/types/SUser.d.ts
+++ b/tools/syn2mas/src/types/SUser.d.ts
@@ -21,4 +21,5 @@ export interface SUser {
   is_guest: number;
   deactivated: number;
   creation_ts: UnixTimestamp;
+  appservice_id?: string;
 }