Opportunistic Routing (OR) has been proposed to improve the efficiency of unicast protocols in wireless networks. In contrast to traditional routing, instead of preselecting a single specific node to be the next-hop forwarder, an ordered set of nodes (referred to as candidates) is selected as the next-hop potential forwarders. In this paper, we propose a new multicast routing protocol based on OR for wireless mesh networks, named Multicast OR Protocol (MORP). We compare our proposal with the well known ODMRP Multicast protocol. Our results show that Multicast-OR outperforms ODMRP, reducing the number of transmissions and increasing the packet delivery ratio.