The impact of two science enrichment programs on the science attitudes of 330 gifted high school students was evaluated using a multimethod, multiperspective approach that provided a more comprehensive evaluation of program impact on science attitudes than did previous assessments of science programs. Although pre–post comparisons did not indicate positive impact on science attitudes, other measures provided strong evidence of program effectiveness. Program benefits were greater among girls, those who had more supportive families and teachers, and those who entered the programs with greater general confidence in their abilities. Implications for science enrichment programs and their evaluation are discussed. © 2001 John Wiley & Sons, Inc. J Res Sci Teach 38: 1065–1088, 2001