The authors assessed the effects of out-of-school hours academic coaching on students' (at academic performance on end-of-year examinations in English, mathematics, and science; (b) attainment of academic scholarships; and (c) acceptance to Gifted and Talented (GT) classes and selective high schools. Participants were 1,724 elementary and secondary school (Years 4 to 12) students. Results of analysis of covariance, with IQ as the covariate, indicated that coached and uncoached students performed equally in most subjects across most of the academic school years from Year 7 to Year 12. Logistic regression indicated that IQ was the best predictor of outcome for all aptitude tests. However, coaching had a significant effect on success on the GT entrance examination, a lesser impact on entrance to selective high schools, and no impact on the scholarship examination. Intensive test-wiseness and test-taking skills training appears to have compromised the integrity of some selective entrance examinations, particularly for younger students.Key words: commercial academic coaching, effects on performance and aptitude tests, elementary and secondary students in Australia