OBJECTIVE: The aim of the study was to evaluate the feasibility and potential effects of a workplace intervention to reduce and break up sitting. METHODS: Office workers were randomized in clusters to intervention ( n = 22) or control ( n = 22). The intervention included a height-adjustable workstation, education, computer prompt software, and line manager support. Outcomes included device-measured workplace sitting and ecological momentary assessed workplace productivity. Recruitment, retention, and data completion rates were assessed. RESULTS: Recruitment ( N = 44), retention (91%), and workplace sitting measurement rates demonstrated study feasibility. At 8 weeks, workplace sitting was 11% lower (95% CI: -20.71, -1.30) in the intervention group compared with control participants. Intervention participants were also more engaged, motivated, and productive while sitting ( P ≤ 0.016). CONCLUSIONS: It was feasible to implement and evaluate this office workplace intervention, with potential benefits on workplace sitting and ecological momentary assessed productivity.