An assembly line is an industrial arrangement of machines, equipment, and operators for continuous flow of workpieces in mass-production operations. In an assembly line balancing problem, tasks are allocated to workstations according to their processing times and precedence relationships amongst tasks. Nowadays, some research investigated the reliability of assembly production by taking account of task time uncertainties. Our research utilizes uncertainty theory to model task time uncertainties and introduces the belief reliability measure to the assembly line production for the first time. We proposed a multi-objective optimization model that aimed at maximizing the belief reliability and minimizing the cycle time. The problem is solved using a newly developed restart neighborhood search method. The numerical experiments are conducted to verify its efficiency. The methodology proposed in this paper is applicable to any industry (including the automotive industry) when the historical data on task processing times are very scarce. INDEX TERMS Assembly line balancing, belief reliability, neighborhood search, uncertain task times. A. ASSEMBLY LINE BALANCING WITH UNCERTAIN TASK TIMES Nowadays, ALBP with uncertain task times (ALBP-UT) receives a lot of attention in academia. Task time uncertainty may result from instability of the operator's work rates, the varied skills and motivations of workers, and the failure sensitivity of complex processes' uncertainty [3]. Suresh and Sahu [29] first introduced the task time uncertainty into ALBP and proposed a simulated annealing algorithm. Baykasoğlu and Özbakir [2] optimized a U-shaped ALBP-UT by genetic algorithm. Cakir et al. [6] proposed a hybrid simulated annealing algorithm to solve the multi-objective ALBP-UT. More recently, Delice et al. [7] developed a genetic algorithm to solve the two-sided U-shaped ALBP-UT. Li [12] solved the type-II ALBP-UT by a branch-and-bound