Several models have been developed for understanding and predicting innovation adoption in organizations and literature has identified several factors that impact the adoption and implementation of Information Technology (IT). This research examines the process of adoption of IT innovations in organizations. The study explores the processes involved in the adoption of IT and verifies the key factors that influence IT innovation adoption in organizations. Using a systematic literature review, the study developed a conceptual model of IT innovation adoption in organizations. The model is a theoretical combination of Diffusion of Innovation (DOI) theory, Theory of Reasoned Action (TRA), Technology Acceptance Model (TAM), Theory of Planned Behaviour (TPB) and a framework which contains characteristics of innovation, organization, environment, chief executive officer (CEO) and user acceptance. The model represents IT innovation adoption as a stage-based process, progressing from initiation to adoption-decision to implementation. The study aggregated findings of past research on IT adoption to identify key factors that influences IT adoption in organizations. The study performed a meta-analysis of innovation, organization, environment, CEOs and user acceptance determinants to assess the magnitude and the strength of these factors on IT innovation adoption. Results confirmed that relative advantage, compatibility, cost, observability and trialability are strong determinants of IT innovation adoption. In terms of organizational context, IS department size, top management support, organizational size, IT expertise, product champion, IS infrastructure, information intensity, resources and specialization was found influential in the adoption of IT. As for environmental characteristics, the meta-analysis verified the significance of external pressure, government support and competitive pressure. Meta-analysis results verified that CEO‟s innovativeness, attitude and IT knowledge as key determinants. The findings confirmed the importance of perceived usefulness, perceived ease of use, subjective norm and facilitating conditions for the user acceptance of IT in organizations.