International comparisons suggest that middle school American students compare poorly to their international peers in tasks that require spatial skills. This deficiency in spatial skills is more prominent in females and has been linked to a lack of developmental activities influenced by gender norms. These deficiencies are especially concerning as increased spatial skills have been repeatedly linked to success in technology and broader STEM learning environments. In females, increased spatial skills have also been linked to positive affective outcomes. Formalised approaches to spatial skill development in middle school are rare and their effectiveness is often limited due to a failure to incorporate the perspectives of practitioners when developing said programs. This paper analyses teacher perceptions of a program designed to address spatial skill development in middle school children. The analysis is based on data collected from the 13 teacher participants at the end of each the 9 modules within the initial program delivery. An outline of program development and examples of materials used are provided. Thematic analysis is used to examine teacher perceptions of program effectiveness and student affect. The findings highlight the impact of teacher perceptions on fidelity of implementation and the need for tailored professional development. Implications for further program development, teacher professional development opportunities and the role of the practitioner in curriculum development are discussed. [For the corresponding grantee submission, see ED609821.]