The benefits of physical activity in school settings and its impact on health and academic outcomes are of interest from public health and educational contexts. This study investigates how physically active learning (PAL): (i) contributes to children's physical activity levels, (ii) impacts on academic outcomes and (iii) influences children's focus and concentration, defined as time on task (ToT). Methods: Over a 2-week period, participants were exposed to PAL and non-active learning (NAL) lessons in a counterbalanced design. Physiological responses and ToT behaviour were recorded throughout PAL and NAL lessons. Academic outcomes were assessed the week before, during and the week after each mode of delivery. Results: Children were more active during PAL (196542 steps per week) compared to NAL (152395 steps per week, P = 0.003). The physiological demands of PAL (73% HRmax), were significantly greater (P < 0.001) than NAL (51% HRmax). Children's ToT was significantly higher (P < 0.001) with PAL (97%) than NAL (87%). There were no differences in academic outcomes when PAL and NAL were compared. Conclusions: Modest levels of PAL increased activity levels. No evidence was found to suggest PAL had a negative effect on children's academic outcomes, and PAL could positively impact on children's concentration.