The objective of this meta-analytical study was to investigate concentrations of milk unsaturated fatty acids (UFA), including C14:1, C18:1, C18:2, CLA, C18:3, C20:1, C20:2, C20:4, docosapentaenoic (DPA), and eicosapentaenoic acid (EPA) in whole raw bovine milk from different production systems (conventional (CNV) vs organic (ORG)) and countries of origin. Data from 18 studies and 13 countries were used to create a data set, which was used for statistical analyses. Data are reported in milk fat percent. The average concentrations of C18:2 and C18:3 in the raw milk from CNV system were greater (1.94, and 0.60 respectively) than those coming from ORG farms (1.90, and 0.54%, respectively), but difference reached no significance. In addition, there were greater concentrations of C20:4 (0.14%) in the raw milk from CNV vs ORG system (0.11%) (P < 0.05). Lower (P < 0.05) amounts of C14:1 (0.76%), C20:1 (0.17%), C20:2 (0.03%), and EPA (0.04%) were reported for milk originating from ORG vs CNV (0.97, 0.26, 0.13, and 0.10%, respectively). In addition, no differences with regards to C18:1 (P = 0.90), CLA (P = 0.31), and DPA (P = 0.07), were reported for milk from the ORG vs CNV system. Country of origin had significant effect on concentrations of UFA (P < 0.05). The lowermost concentrations of C18:1, C18:2, and C20:4 were reported in Germany (P < 0.04%), whereas the greatest levels of those UFA were reported in Belgium and US (P < 0.05). Milk from Poland had lower amounts of C14:1 and C20:1 compared with milk from Germany and Norway, respectively (P < 0.05). Average DPA levels varied from 0.01% (Norway) to 0.19% (Switzerland). Moreover, milk from UK had greater means of C18:3 and CLA compared with milk from Norway and Netherlands, respectively (P < 0.05). Norwegian milk had greater EPA levels compared with milk from China (P < 0.05).In conclusion, data from this meta-analytical study indicated that ORG farms were characterized by greater concentrations of n-3 FA (CLA, DPA, EPA) in the milk compared with milk from the CNV system. This study also showed high variability in concentrations of UFA in raw milk with regards to the country of origin.