Objective: To assess the association between descriptive social norms for weight and weight-related behaviors and associated behaviors at the worksite.

Design and Sample: Baseline data from site-randomized trial of a worksite ecological intervention for weight control; 12 public high schools in central Massachusetts; Sample of 844 employees enrolled (~ 2/3 of all employees).

Conclusions: Associations of weight loss and eating social norms with behavior; Unique from social support; No association of physical activity social norms with physical activity; May be little opportunity for and therefore little exposure to physical activity during the workday; Results support the development of weight loss interventions that address social norms for weight loss and eating behaviors at work.