Although cloud computing is associated with organizational agility, anecdotal evidence points to resistance to cloud computing by employees in information technology (IT) units. We explored the links between software as a service (SaaS) and organizational agility by conducting two stages of interviews with key informants in large organizations, and by employing affordance and inertia-theoretical lenses. Two basic affordances emerged from the retroductive data analysis – implementing quickly and sourcing independently – which in turn yielded two higher-level affordances: trialing alternatives and self-organizing business teams. We developed a model that explains how and why these four affordances enhance agility by accelerating the sensing-to-acting process of organizations. We also describe how five categories of organizational inertia in IT units hinder agility. Our main contribution is how adopting SaaS applications enables organizational agility while highlighting the role of IT unit inertia in SaaS affordance actualization processes.