Employing the phenomenological qualitative research design, this study explores the prevailing pedagogical belief and experiences of six secondary school teachers concerning their practices related to assessment of learning in science subjects among the public secondary school students in the Division of Cagayan de Oro City, Philippines. Anchored on the Theory of Reasoned Action (TRA) argument that additional factors, referred to as external, which in the case of this study pertain to pedagogical beliefs and mandate from the curriculum guide issued by the Department of Education, can influence the behavior of the teachers towards assessment strategy choices. This study has been done to verify whether external factors play a role with the teacher's behavior. Employing the directed content analysis, the data were analyzed in the framework of TRA. Employing the directed content analysis approach, findings of this study suggest that the assessment of learning practices of the teachers are shaped by their pedagogical beliefs, social norms and intentions. This study contributes to an understanding whether external factors directly shape the teacher's behavioral intention to carry out a certain assessment strategy to measure student's learning.