This study aims to improve: (1) the learning process quality, (2) the students' activities, (3) their social attitudes, and (4) their Social Studies learning outcomes through the application of the problem-based learning model assisted by picture stimulant media at SMP Negeri 1 Tepus, Gunungkidul, Yogyakarta. This was an action research study. The data were analyzed by means of the descriptive statistics by comparing the students' learning outcomes before the action with those after the action. The results of the study were as follows. (1) There was an improvemen in the students' attitude. quality scores first cycle of 3; second cycle of 3.7; and the third cycle was 4. (2) There was an improvement in the students' activities; the score was 11.67, improving to 14.17 at the end of Cycle I, 18.80 at the end of Cycle II, and 20.03 at the end of Cycle III. (3) There was an improvement in the students' social attitudes; the mean score was 26.86 at the initial condition, improving to 33.90 at the end of the action. The mean score of their interests was 39.63at the initial condition, improving to 42.67 at the end of the action. (4) There was an improvement learning outcomes; at the initial condition the mean score was 65.50 with a whole class mastery of 50%, improving to 73.50 with a whole class mastery of 70% at the end of Cycle I, 76.17 with a whole class mastery of 76.67% at the end of Cycle II, and 80.00 with a whole class mastery of 86.67% at the end of Cycle III.