Data from 37 peer-reviewed papers were summarized to examine the effect of canola meal (CM) in diet on the performance of dairy cows. The effects were compared by raw mean differences (RMD) between CM diet and control treatment means and weighted by inverse variance using random-effect models. Control treatments (28.6 ± 6.9 kg milk/d) were soybean meal (SBM; 57%), dried destillers grains and solubles (DDGS; 21%), corn gluten meal (7%), cottonseed meal (5%), sunflower meal (2%) and other protein sources (9%). Heterogeneity level was analyzed by I² statistic (low ≤25%; moderate = 26 to 50%; and high >50%). In overall, use of CM as protein source increased DM intake (RMD = 0.22 ± 0.12 kg DM/d; P < 0.01; n = 79; I² = 9.1%) and crude protein (CP) intake (RMD = 0.14 ± 0.07 kg CP/d; P < 0.01; n = 33; I² = 21.1%), but it did not affect organic matter total-tract digestibility (P = 0.50; n = 12; I² = 29.2%). In overall, use of CM increased milk yield (RMD = 0.69 ± 0.35 kg/d; P < 0.01; n = 88; I² = 74.9%), but its effect depends on protein sources comparation: replacement of CM versus SBM did not affect milk yield (RMD = 0.23 ± 0.66 kg/d; P = 0.50; n = 50), but milk yield increased with CM compare with DDG (RMD = 2.03 ± 1.67 kg/d; P < 0.01; n = 18) and other protein sources (RMD = 0.82 ± 0.43 kg/d; P < 0.01; n = 20). In overall, CM use did not affect milk protein content (P = 0.08; n = 60; I² = 19.5%) and milk fat content (P = 0.20; n = 60; I² = 16.9%), but CM increased milk protein yield (RMD = 0.02 ± 0.01 kg/d; P < 0.01; n = 60; I² = 0%). Use of CM reduced milk urea nitrogen (N) (RMD = −0.98 ± 0.31 mg/dL; P < 0.01; n = 22; I² = 32.2%) and increased N intake milk efficiency (RMD = 0.22% N milk/N intake ± 0.07 mg/dL; P ≤ 0.05; n = 34; I² = 0%), both with low heterogeneity. We concluded that CM is similar protein source to SBM and it is more effective than DDG and other sources (cottonseed meal, corn gluten meal and sunflower meal) to lactating dairy cows.