State governments establish pension systems to provide retirement benefits to public employees. State governments as sponsors, state legislatures as policy makers, and public-sector unions as representatives of public employees may exert considerable influence over the decisions made in pension systems. This study applies a system framework to examine these influences. It focuses on four decisions in pension systems: benefits, employer contributions, employee contributions, and the asset smoothing period. The findings show that changes in the short- and long-term financial conditions of a state government have different influences on pension decisions, and that legislatures and public employee unions play important roles that affect these decisions.