While many university health science programs include physics courses to raise knowledge and understanding of physical science concepts, they are still far from addressing the needs of that science health profession. This study aimed to investigate the effect of an introductory physics course on first-year physiotherapy and rehabilitation (PR) students' conceptual understanding of simple electric circuits. The study participants were students enrolled in the Physics II course. Eighty-two students registered for the course. Sixty students (73%) took the pretest, and 67 (81%) completed the posttest. 53 students (64%) took the pretest and posttest. This study adopts an exploratory research methodology that includes a one-group pretest-posttest design. The Simple Electric Circuits Diagnostic Test (SECDT) was used to assess students' conceptual understanding. The prevalence of misconceptions was relatively low (before and after instruction), and very few students developed sound conceptual understanding after instruction. The local reasoning model was the most frequent misconception PR students held. After instruction, students' overall confidence in their SECDT responses increased significantly. Interestingly, when the students were grouped into three achievement groups, the medium-achievement group fell into more misconceptions as their achievement increased compared to low- and high-achievement groups. These findings suggested that students' low SECDT scores were due to a lack of knowledge rather than misconceptions.