This research aimed to examine the influence of critical success factors (CSFs) on the adoption of ERP from three perspectives: organizational, environmental, and technological, and whether the effect of these factors differs under different levels of firm size. Research data were collected from managers in manufacturing firms in Jordan through an online survey. 370 respondents were analyzed by using PLS-SEM. The findings revealed that support from top management, employee IT skills, and cost had no impact on adopting an ERP system, while providing support, competitive pressure, compatibility, relative advantage, and complexity significantly impacted the adoption. In addition, the impact of these factors varied across different levels of firm size. 2022 International Conference on Cyber Resilience (ICCR)