diff --git a/ChangeLog.txt b/ChangeLog.txt
index 02782d30..d51cdd20 100644
--- a/ChangeLog.txt
+++ b/ChangeLog.txt
@@ -18,6 +18,8 @@ Broker:
 
 Client library:
 - Fix topic matching edge case.
+- Fix callback deadlocks after calling mosquitto_disconnect(), when using the
+  threaded interfaces. Closes bug #1313725.
 
 General:
 - Use $(STRIP) for stripping binaries when installing, to allow easier cross
diff --git a/lib/net_mosq.c b/lib/net_mosq.c
index 42ea4ce9..a3977e25 100644
--- a/lib/net_mosq.c
+++ b/lib/net_mosq.c
@@ -776,6 +776,7 @@ int _mosquitto_packet_write(struct mosquitto *mosq)
 				mosq->on_disconnect(mosq, mosq->userdata, 0);
 				mosq->in_callback = false;
 			}
+			pthread_mutex_unlock(&mosq->callback_mutex);
 			pthread_mutex_unlock(&mosq->current_out_packet_mutex);
 			return MOSQ_ERR_SUCCESS;
 		}