This study investigated the basic spatio-temporal gait measures of 898 primary school-aged children (5-13 years) and 82 young adults (18-27 years). Participants completed 6-8 walks at preferred speed along a GAITRite walkway whilst barefoot and whilst wearing athletic shoes or runners. Outcome measures (non-normalized and normalized) were gait speed, cadence, step and stride length, support base, single and double support, stance duration, foot angle and associated symmetry measures. Non-normalized measures of speed, step and stride length, support base and foot angle increased with age whereas cadence reduced. Normalized measures remained unchanged with age in children whereas the young adults (both conditions) exhibited a 2.3% reduction in single support, a 5.1% increase in double support and a 2.6% increase in stance duration (p<0.0001). For the entire sample, shoes increased walking speed by 8 cm s(-1), step length by 5.5 cm, stride length by 11.1 cm and base of support by 0.5 cm. In contrast, foot angle and cadence reduced by 0.1 degrees and 3.9 steps min(-1) respectively. Shoes increased both double support (1.6%) and stance time (0.8%), whereas single support reduced by 0.8%. Symmetry remained unaffected by age. On average, measures of step and stride symmetry (combining both conditions) fell around 0.7 cm, whereas measures of symmetry for step and stance time, single and double support fell around 0.6%. Footwear significantly affected gait (p<0.0001). Gait may not be mature by age 13. Gait is symmetrical in healthy children and young adults but may change with pathology.