Introduction: The purpose of this study is to identify the main factors that influence teachers' decision-making regarding the educational use of ICT (Information and Communication Technologies) in technology-rich classrooms. Method: We collected data from 278 teachers in Catalonia (Spain) working in eight primary and secondary education schools rich in educational technology. The specific questionnaire used to that end includes an extensive range of items to obtain information about the teachers' perceptions of the factors influencing the use of ICT in the classroom. Results: We have identified and characterized five factors that influence the educational use of ICT in the classrooms, which in this study we call: utility and educational setting, teacher support, availability and access in the classroom, technological expertise and access outside the classroom. Conclusion: These results may be useful for fostering improved integration processes for ICT in the classroom, and also for focusing teaching training about this content.