The research aims to test whether a computer-assisted abstract algebra instruction has significant influence on students’ achievement levels and their attitudes toward the mathematics. The sample of the study consists of a total of 30 students studying in the elementary mathematics teacher training program of the faculty of education of a state university in Turkey. The methodology of this study is nonequivalent pretest-posttest control group experimental design. The traditional teaching method was used in the control group and the ACE (activities, class discussion, exercises) teaching cycle based on the APOS theoretical framework was used in the experimental group. In this framework, ISETL programming language was used in the computer activities which was the first step of ACE cycle in the experimental group. The data were collected through academic achievement test, math attitude scale and interviews. The results showed that the use of ISETL programming language in abstract algebra teaching increased academic achievement and attitudes towards mathematics course. Findings from interviews showed that the experimental group students' understanding of the concepts of normal subgroup and quotient group was more advanced than the control group students.