Lockie, RG, Orr, RM, Montes, F, Ruvalcaba, TJ, and Dawes, JJ. Impact of physical fitness on reasons for academy release in firefighter trainees. J Strength Cond Res 37(7): 1515-1522, 2023-Firefighter trainees require a certain level of fitness to be admitted to and to complete a fire training academy. There is no research detailing whether there are fitness differences between trainees who graduate (GRAD) or those released due to either injury (RELI) or skills test performance failures (RELP). Archival data from 305 trainees (274 males and 31 females) were analyzed. Trainees completed the following fitness tests at the start of academy: Illinois agility test, metronome push-ups, pull-ups, leg tucks, multistage fitness test, backward overhead medicine ball throw (BOMBT) with a 4.54-kg ball, 10 repetition maximum deadlift, and a farmer's carry with 18-kg kettlebells over a 91.44-m course. Trainees were split into GRAD (245 males and 16 females), RELI (9 males and 1 female), and RELP (20 males and 14 females) groups. Kolmogorov-Smirnov data indicated most data were not normally distributed. Accordingly, Kruskal-Wallis H-tests, with Bonferroni post hoc, calculated between-group fitness test differences. Effect sizes were also derived. Except for the leg tuck and farmer's carry, the RELP group performed significantly poorer in all fitness tests compared with the GRAD group (p ≤ 0.032). The largest effects were seen for the BOMBT (d = 1.02), Illinois agility test, and 10 repetition maximum deadlift (both d = 0.78). There were no significant fitness test differences for the GRAD and RELI groups. Trainees with poorer fitness were more likely to be released from academy due to skills test failures. Multiple fitness components, but particularly muscular strength and power, should be developed in trainees to aid their ability to perform academy firefighting tasks.