Coaches' leadership behaviours are an integral component of the youth sport environment (Vella, Oades, & Crowe, 2013). However, research examining coaches' real-time leadership behaviours in youth sport is limited. The aim of the present study was to explore the leadership behaviours that coaches exhibit and to investigate the association between these behaviours and athletes' motivational outcomes. Twenty-one male youth competitive ice hockey coaches were observed over multiple practice. 291 athletes (Mage = 14.15 years; SD = 1.27, 73% male) completed measures of self-determined motivation (Pelletier et al., 1995), psychological need satisfaction (LaGuardia, Ryan, Couchman, & Deci, 2000), and motivational climate (Smith, Cumming, & Smoll, 2008). Coaches' behaviours were assessed using the Coach Leadership Assessment System (Turnnidge & Côté, 2016). Results revealed that coaches used a range of behaviours, with a predominant use of neutral coaching behaviours (M = 68.30%, SD = 13.19), followed by transformational (M = 25.12%, SD = 11.54), and transactional (M = 4.25%, SD = 2.82) coaching behaviours. Coaches exhibited low levels of laissez-faire (M = 1.74%, SD = 4.50) and toxic (M = 0.4%, SD = 0.85) coaching behaviours. Multilevel analyses demonstrated that at the team level, coaches' observed leadership behaviours were not linked to athletes' self-determined motivation, but accounted for between 2-16% of the variance of athletes other motivational outcomes. The findings extend past research by examining coaches' moment-to-moment leadership behaviours and the hierarchical effects of leadership behaviours on youth's motivational outcomes in sport. Practical recommendations as well as avenues for future research are discussed.