The research aimed at learning: 1) the character of SMA Negeri 7 Yogyakarta students before provided with Islamic guidance and counseling services; 2) character of SMA Negeri 7 Yogyakarta students after provided with Islamic guidance and counseling; and 3) the effectiveness of Islamic guidance and counseling services in improving SMA Negeri 7 Yogyakarta students’ character. The research is an experimental research with one group pretest-posttest design. The population of the research is all SMA Negeri 7 Yogyakarta students in grade XI and XII. The samples were 2 classes namely class of XI MIPA 3 and class of XII MIPA 4 for the experiment groups and 2 other classes namely class of XI MIPA 5 and XII IPS 2 for experiment class with purposive sampling. The data were collected using questionnaire. The data analysis technique was independent t test sample. The research result indicated 1) the characters of SMA Negeri 7 Yogyakarta students before provided with Islamic guidance and counseling services were in good category with the score of 94,7231; 2) the characters of SMA Negeri 7 Yogyakarta students after provided with Islamic guidance and counseling services were in good category with the score of 101,7538; and 3) Islamic guidance and counseling services were effective in improving the characters of SMA Negeri 7 Yogyakarta students with t-count -14,967 and p 0,000 (p<0,05). The effectiveness of Islamic guidance and counseling services in improving the characters was in medium category with effect size of 0,7426.