In this paper, we propose a permission-based message efficient mutual exclusion (MUTEX) algorithm for mobile ad hoc networks (MANETs). To reduce messages cost, the algorithm uses the “look-ahead” technique, which enforces MUTEX only among the hosts currently competing for the critical section. We propose mechanisms to handle dozes and disconnections of mobile hosts. The assumption of FIFO channel in the original “look-ahead” technique is also relaxed. The proposed algorithm can also tolerate link or host failures, using timeout-based mechanisms. Both analytical and simulation results show that the proposed algorithm works well under various conditions, especially when the mobility is high or load level is low. To our knowledge, this is the first permission-based MUTEX algorithm for MANETs.