Abstract
The concept of physics consists of concrete and abstract concepts. Students should be able to master the concept of physics as well as to be able to solve problems in physics. Students' concept mastery can be improved by technology-based learning. The study was conducted at three different high schools. We investigated the students' mastery improvement in physics learning assisted by virtual lab media. The sample was chosen using purposive sampling resulting 34 male students and 36 female students. The results showed that there was an increase in entire students' concept mastery. In general, male students' mastery of the concept was higher than the female students. In particular, male students demonstrated higher mastery of higher concepts on higher cognitive aspects (analyzing, synthesizing, creating), while female students had a higher ability in the lower cognitive aspects (remembering, understanding, and applying).