Annual companion crops are often used in new seedings of perennial forages in western Canada. Fast-establishing grass species that do not overwinter in this region have potential as companion crops to increase seeding year yields without reducing perennial forage establishment. Trials were seeded in two different years at Saskatoon and Melfort, SK, in the Dark Brown and Black soil zones, respectively. Crested wheatgrass [Agropyron cristatum (L.) Gaertn.], meadow bromegrass (Bromus riparius Rehm.), and alfalfa (Medicago sativa L.) were seeded in pure stands and mixtures with or without an annual ryegrass (Lolium multiflorum Lam.) or Festulolium (Lolium × Festuca) companion crop at two seeding rates. Forage dry matter yield in the establishment year was increased with annual ryegrass companion crops compared with no companion crop regardless of seeding rate, but was increased only with the higher rate of Festulolium at Saskatoon. Despite using low companion crop seeding rates, stand densities of most of the perennial forage stands were lower than with no companion crop at Saskatoon, but in Melfort, most stand densities did not differ. The annual ryegrass companion crop reduced yields the year after seeding at both sites, while the Festulolium also reduced yields, but not at Melfort for the lower companion crop seeding rate. Dry matter yields were usually not different between companion and no companion crop treatments in the second year after seeding and for 3-yr total yields. The use of these companion crops increased the percentage of the 3-yr total yield produced in the seeding year.