The differences related to gender are evident in physics education from the early age of the students. Thus, it is important that the teaching strategies that are implemented in mixed-gender physics classrooms are appropriate for both boys and girls. This research examined physics achievement and metacognitive awareness of students in lower secondary education in relation to gender when the modified Know-Want-Learn (mKWL) strategy is implemented. During the study, the students were divided into the control group (where direct teaching was implemented) and the experimental group (where the mKWL strategy was implemented in physics teaching). Students' physics achievement (estimated with knowledge tests) and metacognitive awareness (estimated with a questionnaire) before and after the pedagogical experiment, and also the students' comments on the mKWL strategy (provided through an informal conversation) were analyzed. It was shown that the students' achievement did not differ in relation to gender while girls showed higher metacognitive awareness in comparison with boys, and the mKWL strategy increased physics achievement and metacognitive awareness of both boys and girls. Furthermore, the students' comments on the strategy were discussed. The proposed strategy is shown to be appropriate for both genders, and its implementation in physics classrooms can be recommended.