The effects of 10 commercial canola, Brassica napus L., cultivars widely grown in Iran—‘SLM₀₄₆,’ ‘Opera,’ ‘Okapi,’ ‘RGS₀₀₃,’ ‘Modena,’ ‘Sarigol,’ ‘Zarfam,’ ‘Licord,’ ‘Hayula₄₂₀,’ and ‘Talaye’—on the demographic parameters of diamondback moth, Plutella xylostella L. (Lepidoptera: Plutellidae), were determined. The experiments were conducted in a growth chamber at 25 ± 1°C, 65 ± 2% RH, and aphotoperiod of 16:8 (L:D) h. The comparison of intrinsic rate of natural increase (r_m), net reproductive rate (R₀), and the survival rate of adult stage of P. xylostella on 10 canola cultivars suggested that this pest performed best on SLM₀₄₆. The r_m value of P. xylostella ranged between 0.241 on RGS₀₀₃ and 0.304 on SLM₀₄₆. The R₀, finite rate of increase (λ), mean generation time (T), and doubling time (DT) values of P. xylostella on SLM₀₄₆ were 52, 1.35, 13.4, and 2.35 and on RGS₀₀₃ were 31, 1.27, 14.4, and 2.94, respectively. The Weibull model adequately described the shape of the survivorship curve of adult P. xylostella from life-table data. A significant fit was obtained with the Weibull model for P. xylostella in all experimental canola cultivars. As a result, SLM₀₄₆ Opera, and Hayula₄₂₀ were the most suitable hosts and had least negative impact on life-history statistics of the pest.