The article presents results of research conducted on a large sample (N = 1,316) of youths of both sexes (49% men and 51% women) from two categories of schools--public or state (68%) and non-public or private (32%). Participants' creative ability and style of creative functioning was assessed using Urban & Jellen TCT-DP (to assess level) and Kirton Adaption-Innovation Inventory (to assess style). GPA served as an indicator of the effectiveness of school functioning, which overall was found to be weak. It did correlate significantly and positively with creative ability levels, but not innovativeness-adaptiveness. Positive correlations exist between GPA, originality and efficiency as determined by the KAI subscales. Interesting differences exist between the two types of schools. A creative thinking and originality style of functioning influenced grades significantly in public schools. In non-public schools efficiency of functioning was more important to school success. Creative innovators appeared most efficient in public schools, compared with non-creative innovators. Adaptors in non-public schools tend to be slightly more efficient, especially if they are creative. The results are discussed in terms of the assumed independence of creativity level and style formulated by M. Kirton (1976, 2003) and sources of school success in different types of schools in Poland. (Contains 3 tables and 1 figure.)