The report by the United Nations in 2020 stated that Afghanistan was ranked 118th position in the e-participation index which shows the low level of adoption among the Afghan citizens to online services offered by the e-government websites in Afghanistan. As no previous research has been conducted to explore the influential factors on the adoption of e-government websites in Afghanistan, this research fills the research gap by exploring the impact of website quality factors, trust factors, and technology adoption factors on intention to use e-government websites from the citizens' perspective in Afghanistan. This research also investigates the impact of factors on the adoption of governmental websites at three levels (information, interaction, and transaction) of e-government maturity. As part of the current research, the unified model of e-government adoption (UMEGA) model was extended by integrating website quality factors and trust factors, which were extracted based on an extensive literature review. To validate the model, a survey of 294 Afghan citizens was conducted in four provinces of Afghanistan. The data were then analyzed using the partial least square-structured equation modeling (PLS-SEM) technique. The result revealed that websites quality, technology adoption, and trust factors have major impacts on the adoption of e-government websites in Afghanistan, the impact of which varies depending on the level of e-government maturity. Public administrators, officials, policymakers, website designers, and researchers have potential implications from the findings of this research regarding the adoption of governmental websites in Afghanistan.