The design of routing protocols for Low-Power and Lossy Networks (LLNs) is complicated by the inherent complexity of the environment and challenging wireless link quality. Nevertheless, the broadcast nature of wireless communications has been exploited by opportunistic routing and network coding to increase transmission efficiency and capacity in wireless networks. Opportunistic routing selects the most suitable relay node from multiple potential candidates when forwarding data, increasing the delivery probability. Meanwhile, network coding encodes multiple packets and transmits them collectively thereby increasing the transmission capacity. Therefore, an opportunistic routing protocol combined with network coding technology can further improve the throughput and realize more efficient data transmission in the challenging LLN environment. We propose a Network coding-based Energy-efficient Opportunistic routing Protocol (NEOP) where the fundamental premise of the algorithm is as follows: in order to identify the optimal next-hop node, the NEOP algorithm initially determines the set of potential forwarding nodes, and then makes coding decisions based on the data packets present in the node buffer. This ensures that the coded packets can be successfully decoded. To achieve energy-efficiency, the nodes’ residual energy is included as routing metric, thereby enhancing network throughput and reducing energy consumption. The validation using simulations show that in networks with a large number of flows, NEOP significantly improves the network throughput, average energy consumption and delay, in comparison to other similar protocols.