Amidst ongoing calls for teaching improvement, there has been growing interest in the work of middle leaders in leading school-based curriculum and professional development. Research and policy initiatives have acknowledged that these leaders in schools are well placed to successfully drive educational change that leads to improved educational outcomes for students. This has led to an increase in development programmes for middle leaders, but there appears to be a distinctive disconnect between the research and theory that should inform these, initiatives. This article reports findings gathered from a questionnaire completed by almost 200 middle leaders from across Australia, conducted as part of a larger national mixed method research studying middle leader practices. The instrument was designed to investigate the practices of middle leaders who were responsible for leading school-based development, based on three domains of middle leading practices: leading and teaching, managing and facilitating, and communicating and collaborating. Multivariate analysis techniques were used to analyse the data, and there were statistically significant differences in the practices of middle leaders based on school type and their professional accreditation levels. Participant responses related to highlighted high administration workload potentially impacted ML practices related to leading teaching and learning.