Balancing parallel assembly lines provides flexibility to minimise the total idle times of assembly lines and the total number of workstations required in production facilities. This paper proposes two goal programming approaches to balance parallel assembly lines with precise and fuzzy goals. Three conflicting goals, namely number of workstations, cycle time, and number of tasks assigned to a workstation are optimised in crisp and fuzzy environments. The proposed approaches are also illustrated using numerical examples and sensitivity analyses. The proposed approaches provide flexibility for decision makers to balance parallel assembly lines based on their decision environments and preferred priorities.