This study compares e-resources usage by academic staff and researchers across universities in Tanzania. A descriptive cross-sectional design was adopted to administer questionnaire surveys to 170 academic staff and researchers in selected universities. Regarding data analysis, descriptive statistical analysis was done to construct frequencies and percentages alongside Chi-square testing to show differences and establish associations. The study has found a difference in access to and usage of e-resources for supporting teaching and research activities among the universities involved. The findings further indicate that open access resources are significantly used for teaching and research purposes, more so than the subscribed resources. Inability to access full text articles, inadequate searching skills, and slow Internet speed were the main challenges reported to undermine effective access to and use of e-resources. Despite these challenges, the impact of e-resources on teaching and research activities has been confirmed by the study. As a result, the study recommends that librarians closely interact with academic staff and researchers through outreach and marketing programmes to enhance the usage of these resources.