Objective: To examine the associations between potential social ecological correlates and self-reported short physical activity breaks during work hours (defined as any interruption in sitting time during a typical work hour) among a sample of employees who commonly sit for working tasks. Methods: 801 employed adults aged 18-70. years from metropolitan Melbourne, Australia were surveyed in 2009 about their short physical activity breaks from sitting during work hours and potential social ecological correlates of this behaviour. Results: Men reported significantly more short physical activity breaks per work hour than did women (2.5 vs. 2.3 breaks/h, p = 0.02). A multivariable linear regression analysis adjusting for clustering and meeting the public health physical activity recommendations showed that the factors associated with frequency of short physical activity breaks per work hour were perceptions of lack of time for short physical activity breaks for men (-0.31 breaks/h, 95% confidence intervals [CI] -0.52, -0.09) and lack of information about taking short physical activity breaks for women (-0.20 breaks/h, CI -0.47, -0.05). Conclusion: These findings suggest that providing male employees with support for short physical activity breaks during work hours, and female employees with information on benefits of this behaviour may be useful for reducing workplace sedentary time.