Weed management in organic lentil (Lens culinaris Medik.) is challenging due to its poorly competitive nature with weeds and the lack of organic herbicides for field crops. In-crop mechanical weed control methods such as rotary hoeing, harrowing and inter-row cultivation, and the cultural practice of increased crop seeding rate, are established weed management tools in organic field crops. They have however not previously been combined into an integrated weed management system for weakly competitive grain crops. The objective of this research was to determine the effect of mechanical weed control (rotary hoeing, harrowing and inter-row cultivation) and crop seeding rate alone and in combination on weed suppression and yield in organic lentil. A two-factor randomized complete block design experiment was conducted at two locations in Saskatchewan, Canada in 2016 and 2017. The factors mechanical weed control methods including the rotary hoe, the harrow and inter-row cultivation and an untreated control, and seeding rates including conventional recommended and double recommended seeding rate. All treatments were tested as stand-alone or combined in a factorial fashion. Increased crop seeding rate and mechanical weed control affected response variables independently of each other. Doubling the seeding rate of lentil reduced weed biomass by 16% and increased lentil yield by 23% averaged across the four site-years. Treatments that included only a single mechanical weed control methods resulted in poor or incomplete weed suppression at all sites. Two mechanical weed control methods were required to maximize yield, and three were required to minimize weed biomass. Early weed control with a rotary hoe, followed by inter-row cultivation prior to canopy closure was the most consistent mechanical weed control treatment across the four site-years. Averaged across the four site-years, rotary hoeing + inter-row cultivation reduced weed biomass by 70%, and increased crop yield by 65%. The treatment maintained low weed populations across the longest time duration and controlled weeds in both the inter- and intra-row spaces, while minimizing crop injury. Doubling crop seeding rate and using two appropriately timed mechanical weed control methods provided weed suppression while increasing yield by 46% in a weakly competitive organic lentil crop.