Diverse learners attending online K-12 schools deserve high quality and accessible educational programs. This research studies the preparation, knowledge, and practices of online middle school general and special education teachers in relation to supporting the needs of diverse learners, namely students with Specific Learning Disabilities (SLD). A study of the literature indicated online teachers need training and development related to meeting the needs of students with disabilities and researchers call for more studies analyzing the preparedness and support of our teachers to meet the needs of diverse learners. This study responds to this need for action through a quantitative approach to examining the perceptions of middle school teachers across nine online public schools seeking to understand their preparedness, knowledge, and pedagogical practices related to teaching students with SLD in online schools. Teachers expressed a lack of preparation when reflecting on their pre-service training programs, in-service new teacher training and ongoing professional learning. In online schooling, it is necessary for teachers to have technological knowledge and skills to effectively teach all students. The findings from this study support an intervention that aims to improve online middle school teachers' knowledge and skills related to teaching students with SLD in online school environments.