Clustering is believed to be the solution to the needs of energy efficiency as well as scalability in Wireless Sensor Network (WSN) application. In traditional clustering, each node belongs to only one cluster. However, some applications need some nodes to affiliate to more than one cluster. We propose a clustering algorithm that has capability to control the overlapping between clusters with still having ability to maintain the balance of energy consumption. Our proposed algorithm is a modification version of LEACH, so we call ours as Overlapping LEACH (O-LEACH). In the algorithm, we insert a mechanism so that it is able to control the overlap among clusters. In O-LEACH, as in original LEACH, a non-cluster-head (non-CH) will choose to join to a cluster-head (CH) that has largest received signal strength. Next, OLEACH will ask the node to affiliate to other CH that has received signal strength larger than X% from main CH. The X limit value is determined based on the expected overlapping degree. By simulation evaluation, O-LEACH has succeeded to control the overlapping among clusters. The proposed algorithm also still able to maintain the load balancing among node that be proven with the very little degradation compared to original LEACH on the performance of maintaining the balance of energy consumption.