The study aimed to determine the effects of boron concentrations on germination and seedling growth of winter canola varieties under laboratory conditions. Seeds of four winter canola varieties (KWS Cyrill CL, Miranda, PT264, and NK Caravel) were germinated between papers with different boron levels (0, 20, 40, 60, 80, and 100 mg B L-1) consisting of sodium borate (Na2B8O13.4H2O) at 20°C for 7 days. The germination percentage, mean germination time, germination index, seedling growth parameters, and dry matter were measured. The results showed that germination percentage, mean germination time, and germination index were negatively affected by increasing B concentrations. When B levels increased, root and shoot lengths and weights were also inhibited, while the responses of canola varieties differed. Shoot length was strongly affected by B levels, decreasing from 5.15 cm to 1.82 cm and root length from 4.99 cm to 2.59 cm. Under boron stress, KWS Cyrill CL germinated higher and developed longer roots and shoots. Differences in both germination and seedling growth were observed at 80 mg B L-1 and above. It was concluded that there is a genotypic variation among canola varieties concerning boron toxicity and that KWS Cyrill CL is more tolerant to high boron concentrations than the other varieties.