Brock, F, Christopher, J, Harry, B, and Carl, WT. Manipulating field dimensions during small-sided games impacts the technical and physical profiles of Australian footballers. J Strength Cond Res 32(7): 2039–2044, 2018—This study investigated the effect of manipulating field dimensions on the technical and physical profiles of Australian football (AF) players during small-sided games (SSGs). A total of 40 male players (23.9 ± 3.5 years) participated in 3, five-a-side SSGs; defined as “small” (20 × 30 m; 600 m2), “medium” (30 × 40 m; 1,200 m2), and “large” (40 × 50 m; 2,000 m2). Notational analyses enabled the quantification of technical skill indicators, whereas physical activity profiles were measured using microtechnology, resulting in 18 criterion variables. A multivariate analysis of variance modeled the main effect of field dimension on the criterion variables. A significant main effect was observed (V = 1.032; F38, 102 = 2.863; p ≤ 0.05), with the “small” and “medium” SSGs generating more turnovers and ineffective handballs relative to the “large” SSG. Furthermore, the “small” SSG generated more tackles and fewer bounces compared with the “large” SSG. The “large” SSG generated a greater absolute distance, relative distance, maximum velocity, PlayerLoad, and distance >4.16 m·s−1 compared with the “small” and “medium” SSGs. These results provide AF coaches with insights into how task constraint manipulation impacts the technical and physical profiles of players during small-sided game-play. Thus, coaches and physical performance specialists could use this information to assist with the tactical periodization of technical complexity and physical load at different phases of the AF season.