Our study was motivated by a gap identified in the existing literature regarding the factors considered by teacher unions, specifically the Zambia National Union of Teachers (ZNUT) and the Secondary School Teachers Union of Zambia (SESTUZ), during the formulation of the re-entry policy in Zambia. To address this gap, we adopted ontological, epistemological, and axiological approaches within the study process. Employing a qualitative case study design, the study was conducted in Zambia, with a sample drawn from schools, zones, districts, and provinces through convenient sampling. The study population comprised 20 Teacher Union Representatives from ZNUT and SESTUZ and directors from the Ministry of General Education (MoGE). Sample size determination follows recommendations by Creswell (1998) and Morse (1994), resulting in 26 participants. However, due to data saturation, interviews are conducted with 11 union representatives and 4 directors. Data is collected through interviews, and thematic analysis is employed for data analysis. Ethical clearance was obtained from the University of Zambia Directorate of Research and Graduate Studies. The findings reveal that teacher unions sought inclusivity, adequate resources, quality education, support for teachers, protection of learners rights, and policy sustainability during the re-entry policy formulation. The study underscores the pivotal role of teacher unions in the formulation and implementation of education policies, emphasizing the importance of their input for policies to be effective, practical, and inclusive, thereby benefiting the entire education ecosystem.