Inclusive education is a right that has captured the attention of public institutions, researchers, and teaching professionals around the world. The beliefs and perceptions of teachers are a fundamental axis in knowing the state of these professionals regarding this ethical principle, allowing them to develop and implement different strategies. This study aims to explore the reliability and factor structure of the Evaluation of Teachers’ Preparation for Inclusion (CEFI-R) questionnaire among physical education teachers. The sample consisted of 789 Spanish in-service teachers who completed the questionnaire to assess their readiness for inclusion in this subject. Exploratory and confirmatory factor analyses as well as reliability testing were carried out. A factor structure with four dimensions (conception of diversity, methodology, support, and community participation) was obtained. These dimensions consisted of 17 items with good and excellent goodness-of-fit values. In addition, a high reliability was obtained (Cronbach’s Alpha = 0.71−0.93). Therefore, the CEFI-R could be considered a valid and reliable tool to analyze physical education teachers’ perceptions of their preparedness for inclusive education.