The problem-solving processes and strategies of ten school principals with reputations for high effectiveness were studied. Verbal protocols were gathered through unstructured interviews while principals were working on a set of five cases. Analysis of the data was guided, but not constrained, by a set of processes and strategies for problem solving suggested by the models of problem solving developed by Leithwood, Voss, and Mumford. Results describe the categories of problem solving processes that emerged across the five problems, the frequencies with which these processes were used, graphic representations of the strategies principals used to solve the problems, as well as the consistency of using the same strategy across problems. (Contains 2 tables and 4 figures.)