This paper reports the relative effectiveness of Smart and Mainstream schooling in terms of student achievement in science. The participants comprised 770 secondary school Form 3 (15-year-old) students from two Smart Schools and two Mainstream Schools in Malaysia. Using students' Standardised National Examination (SNE) primary-school science achievement results as covariate, SNE lower-secondary science achievement results were analysed using analysis of covariance (ANCOVA). The results indicated that the level of achievement in science of Form 3 students in the Smart Schools was statistically significantly higher than their counterparts in Mainstream Schools with an educationally significant effect size of +0.41. A "statistical triangulation" was provided through follow-up analyses using ANCOVA by school and independent t-tests by entry grade. The former confirmed that the significant group difference was indeed contributed by both Smart Schools while the latter revealed that group difference in science achievement was strongest amongst students with B and C entry grades. The paper discusses the findings in terms of parallel impact comparison within the available literature and recommends that future studies should look into isolating specific elements of the Smart Schools Initiative that have direct impact on student science achievement. (Contains 6 tables and 1 figure.)