The purpose of this study was to examine the correlations between neuroticness, assertivity, and maturity. It was hypotesized that there were relationships between neuroticness, assertivity and maturity; and there was a negative correlation between neuroticness and assertivity, also there was a negative correlation between neuroticness and maturity. The subjects were 95 male and female students of SMK 7 in Yogyakarta, 15 β 18 years old. Three questionaires were applied to measure neuroticness, assertivity, and maturity. Multiple regression analysis was used as a statisticalmethod. Results of the study showed that there was relationship between neuroticness, assertivity, and maturity (F = 6,88; Ry(1-2) = 0,36; p<0,01); and there were positive correlation between neuroticness and asertivity rx1y = 2,12 (p<0,05), there were positive correlation between neuroticness and maturityrx2y = 0,28 (p<0,05). These two minor hypotheses were failed