Reducing sedentary behavior in the workplace has become an important public health priority; however, some employers have expressed concerns regarding the potential for reduced productivity if employees are not seated while at work. Therefore, the aim of this study was to determine the relationship between workplace sedentary behavior (sitting time) and work productivity among full-time office-based employees, and further to investigate other potential factors associated with productivity. A 19-item online self-report survey was completed by 2068 government employees in Kansas. The survey assessed workplace sedentary behavior, work productivity, job satisfaction, and fatigue. Overall, office workers reported high levels of sedentary time (mean > 78%). The primary results indicated that sitting time was not significantly associated with productivity ( β = 0.013, p = 0.519), but job satisfaction and fatigue were positively ( β = 0.473, p < 0.001) and negatively ( β = −0.047, p = 0.023) associated with productivity, respectively. Furthermore, participants with the highest level of sitting time (>91% of the time) reported lower job satisfaction and greater fatigue as compared with the lowest level of sitting time (<75% of the time). Taken together, these results offer promising support that less sitting time is associated with positive outcomes that do not seem to come at the expense of productivity.