In Ontario, spring barley production is tied to major livestock production regions of the province. Although barley yields continue to rise, further innovation to increase yields would benefit livestock producers significantly. Four Ontario adapted barley lines were evaluated as purelines, as well as two way (75:25, 50:50 and 25:75), three-way (33:33:33) and four-way (25:25:25:25) blends in eight environments over two years to determine the effects of blending on yield, thousand kernel weight (TKW) and test weight, as well as a number of other disease and agronomic components. Using diallel analysis, it was determined that no significant general blending ability (GBA) or true general competing ability (TGCA) was noted for yield, however significant GBA was noted for TKW and test weight. Significant general yielding ability (GYA) effects were noted for all three parameters indicating that selecting the best performing lines in pure stand is the most effective way to generate the best performing blends. However, further analysis of blends found that 50:50 blends do not always predict the optimal cultivar blends, as other blend ratios performed better and had higher percent increases in blend response. Stability analysis of blends and purelines found that blends were more stable than purelines for yield and test weight. This research indicates that a further step of the breeding process might be to select the best performing lines from pure stands and then blend them in various ratios to select the optimal spring barley blend for performance and stability.