A field experiment was conducted during winter (Rabi) seasons of 2014-15 and 2015-16 at Punjab Agricultural University, Ludhiana, India to study the effect of potato planting geometry (50 × 15 cm, 65 × 11.5 cm, 70 × 10.7 cm and 75 × 10 cm) and seed tuber size (25-35 mm, 35-45 mm, 45-55 mm) on weed density and biomass, and tuber yield of potato. The potato canopy cover was higher and the weed density and biomass were lower with closer planting geometry of 50 × 15 cm followed by 65 × 11.5 cm. The growth attributes (number of stems/plant and leaf area index), tuber number and tuber yield were not significantly influenced by varying planting geometry. Potato seed tuber size exerted a significant effect on weed infestation resulting in significantly lower weed density and biomass with large sized seed tubers followed by medium sized seed tubers as compared to small sized seed tubers. Growth attributes, tuber number and tuber yield of potato were also significantly higher with large sized seed tubers followed by medium sized tubers compared to small sized tubers. Thus, the potato planting geometry of 50 × 15 cm for manual planting by small and marginal farmers and 65 × 15 cm for mechanized potato production along with medium sized seed tubers are the viable options for effective weed management and optimal potato tuber yield.