Information system (IS) acceptance has received considerable attention in prior research using a variety of dependent variables (DVs) representing intentions and behaviors. This study proposes that task dependence and external control determine the extent of flexibility in IS use faced by individuals. Using a 2 × 2 framework, this study argues that flexibility is high when both task dependence and external control are low while flexibility is low when either task dependence or external control is high. Further, this study suggests that: a) both intention and behavior DVs may be appropriate when flexibility is high, b) adoption and system use may be most appropriate when flexibility is low, and c) the antecedents of adoption and system use need to account for task dependence and external control. This study provides a review of the adoption and system use constructs in recent literature on IS acceptance and offers potential directions for future research.