This survey study explored secondary school physics teachers’ content knowledge of the selected content domains of secondary school physics including: Waves and Oscillations, Heat and Temperature, Electricity and Magnetism and Mechanics. The subsidiary aim was to identify the questions which were responded incorrectly by the majority of participant teachers. Physics Achievement Test (PAT) was adopted from previous research studies and found to be reliable for the sample of this study (α = 0.76). The tool was directly administered to 120 secondary school physics teachers from public (n=57) and private (n=63) schools of tehsil Danyore district Gilgit, Gilgit-Baltistan. Results of the study showed that physics teachers’ overall performance on PAT was 60% of total score (35). Teachers’ performed better than the overall score in all content domains except Electricity and Magnetism (53%). In order to explore the extent of difficulty of each item of PAT, Difficulty Index was computed for all 35 items. Of the 35 items, 5 fell in the difficult range. Moreover, among the cognitive domains teachers’ demonstrated better performance in the items of Application and Knowledge whereas they found Reasoning domain the most difficult. The study provides significant insights into the existing content knowledge of physics teachers for policy, practice and further research. Future research can be benefitted by conducting a large scale study on a bigger and more representative sample for better generalizability.