The research aims to: (1) produce a computer program as a learning resource on gas law topics; (2) determine the appropriateness and quality of the computer program; and (3) describe the effectiveness of the computer program to help students in learning the concept of gas law. We employed 4D (define, design, develop, disseminate) models in this research. The computer program is validated by physics expert, learning media expert, and physics teachers. The appropriateness and quality of the computer program were analyzed descriptively. The field testing involved a small group consists of 4 students and a larger group consists of 61 students. The effectiveness of the computer program in improving students' learning achievement was investigated through one group pretest and posttest design. The results of this study showed that the computer program is feasible for high school physics learning. Based on the assessment by physics experts, learning media experts and high school physics teachers, the quality of computer program can be categorized as very good. Normalized gains from the conducted pretest and posttest to small and larger group are found as 0.68 and 0.55, respectively. It indicates that there is medium improvement of students' learning achievement after using the computer program as a learning resource.