The aim of this study is to develop an understanding of how Formative Assessment Classroom Techniques (FACTs) can be used to develop in-depth student learning in selected topics in Grade 9 physics. The study also explored facilitating and challenging factors associated with the usage of the FACTs-based teaching of the context. The study employed action research method within qualitative paradigm. The data collection was carried out in a private higher secondary school over a period of eight weeks. The data were collected through interviews, observations, reflections and pre- and post- intervention student achievement tests. The findings of the study at the pre-intervention stage revealed that there was a lack of opportunities for student’s involvement in classroom activities having an element of FA in it. As a result of intervention, students were exposed to various FACTs through which they would express themselves, articulate their viewpoint and display their understanding of subject matter knowledge. Moreover, a considerable progression was seen in terms of a shift from students’ low participation to high participation; from weak scientific responses to strong scientific responses (oral and written) and from individual work to collaborative work. In addition, a limited scale quantitative analysis of students’ test scores also revealed the positive impact of FACTs-based teaching on students’ in-depth learning. Besides its facilitating factors, the study highlighted some of the challenges faced in the way of implementing FACTs in the classroom. These challenges ranged from time management (FACTs demand more time and efforts), to lack of teachers’ pedagogical knowledge and resources. The conclusions drawn from the findings suggest that teachers who use FACTs in their classroom on routine basis need support and facilitation at different levels. The school management or system needs to create conditions that are conducive to effective and sustained application of FACTs. As policy implication, it is recommended that FACTs should be introduced in the National Curriculum for physics with proper implementation guidelines to make them more practical in classroom teaching.