The rapid diffusion of learning through smart devices has facilitated information acquisition and improved knowledge sharing. This study analyzes the adoption and diffusion of smart learning from the human resource development (HRD) managerial perspective, based on a modified technology acceptance model which reflects perceived risk (PR) and organizational innovativeness (OI). Further, the results of a comparative analysis on large enterprises and small and medium enterprises (SMEs) reveal that their adoption of smart learning differs. First, large enterprises emphasize perceived ease of use (PEOU) as a reason for adoption, while SMEs emphasize perceived usefulness (PU). Second, while OI affects both types of enterprises, PR is statistically significant only for large enterprises. Finally, mobility and interactivity, important features of smart learning, have different effects on PEOU and PU for the two types of companies. This analysis provides useful guidance for HRD managers, solution providers, and content providers for improving workplace learning and thus creating more value for companies.