Higher educational institutions were forced to stop face-to-face classes and shift to online learning during the COVID-19 pandemic. The government of Ethiopia closed schools in all educational institutions on 16 March 2020, and then directed educational institutions to teach students online. This study was conducted to discover the determinants of online teaching practices at teachers training colleges. A cross-sectional study design was conducted using randomly selected 343 students from Injibara College of Teacher's Education, Ethiopia. Results of the statistical analyses revealed that socio-demographic characteristics of students do not affect the effectiveness of the online learning system; but determinates that are directly related to the online learning system, such as infrastructure, access to the internet, parent support, and technological resources have a significant effect. Online learning at the study area was only 77% effective, which indicates that there is a need for intervention to make it more effective. Therefore, we recommend to governmental and non-governmental institutions to establish ICT centers and provide online learning trainings.