Background and objectives: A meta-analysis of randomised controlled trials (RCT's) was performed to investigate the effects of whole dairy foods and supplements containing dairy ingredients, with and without resistance training (RT), on lean mass, strength, muscle size, muscle protein synthesis and physical function in people aged 50+ years. Methods: RCT's published to March 1 2015 were identified by a comprehensive systematic search of scientific databases. Eligible reports were critically appraised in duplicate. Data were pooled using random-effects meta-analyses. Results: 34 RCT's were eligible for inclusion. Dairy consumed in combination with RT resulted in a small increase in lean mass (weighted mean difference 95% CI; 0.5 0.02, 0.98kg; P=0.04; I2=68%) but had no effect on muscle size (P=0.80), leg press strength (P=0.40) or grip strength (P=0.29). Dairy consumed in the absence of RT had no effect on lean mass (P=0.58). There were insufficient data to analyse gait speed. Dairy protein supplements of different dosages (i.e. 20 vs. 40g/day) increased fractional synthetic rate of myofibrilliar protein both in the context of RT (0.03 0.0, 0.06%/hr; P=0.02; I2=87%) and without RT (0.02 0.01, 0.02%/hr; P<0.001; I2=0%). Conclusions: Increased dairy intake (at least 20 g per day--particularly in the form of dairy protein supplements) when combined with RT, is an effective nutritional strategy to augment lean body mass in people aged 50+ years. While dairy protein acutely up-regulates muscle protein synthesis in this age group irrespective of RT, this effect does not directly translate into increases in regional muscle size, muscle strength or function.