Purpose This study aims to explore the influence of casino servicescape on unplanned gaming behaviors by examining the mediating role of casino customers’ perceived behavioral control (i.e. perceived internal and external control). Design/methodology/approach Data were collected from 475 casino customers using street intercept survey. Multiple regression analysis was used to evaluate the mediating role of perceived behavioral control. Findings Results show a negative indirect effect of casino servicescape evaluation on customers’ unplanned gaming behaviors through perceived internal control. Moreover, casino customers’ perceived external control does not mediate the relationship between casino servicescape evaluation and unplanned gaming behaviors. Research limitations/implications Findings suggest that a favorable casino servicescape may enhance customers’ perception of control over their personal resources (e.g. skills and knowledge), which in turn facilitate self-regulation of their unplanned gaming behaviors. The findings are limited to Chinese casino customers, and researchers should further validate the results for non-Chinese casino patrons. Practical implications To casino operators, results suggest that the Friedman-style casino design (i.e. compact gambling areas and low ceilings) potentially encourages unplanned gaming behaviors of casino customers. From social-policy perspective, governments can create effective responsible gaming programs by enhancing casino customers’ perceived internal control. Originality/value This study illuminates the process that connects casino servicescape with unplanned gaming behavior by explicitly testing the mediating role of customers’ perceived behavioral control. Moreover, it examines unplanned gaming behaviors of leisure gamblers who represent the mass gaming population.