Computational thinking and programming have emerged as central 21st-century skills. Several countries have embedded these skills in their school curricula. This study investigates how an optional programming course affects eighth-grade mathematical problem solving in Norway using a quasi-experimental design with pre- and post-tests. These tests consist of problem solving items from the 2003 Programme for International Student Assessment (Organisation for Economic Co-operation & Development, 2003a). The students taking these tests were divided into two groups: one with students enrolled in an optional programming course and one with students enrolled in other optional courses. Our results indicate no significant difference in the development of mathematical problem solving for the optional programming course students compared with those in other optional courses. Our discussion of these results offers further insights into how problem solving in computational thinking and programming align with mathematical problem solving.