Weed identification is useful for determining their importance and harmfulness in crop production system. Present study aimed to describe the diversity and utilization of weeds in Nainital district, Western Himalaya. A total of 157 species belonging to 118 genera and 35 families were recorded. Asteraceae, Fabaceae, Poaceae, Amaranthaceae, Cyperaceae, Lamiaceae, Polygonaceae, Brassicaceae, Caryophyllaceae, Euphorbiaceae and Rubiaceae were the dominant families. The majority of the weed species were used for fodder (101 species) followed by edible (24 spp.), medicinal (13 spp.) and religious (4 spp.) purpose. For each species, botanical and local names, life form, habit, flowering and fruiting period and utilization pattern were provided.