Cucurbita pepo L. (Cucurbitaceae) was an integral component of the diet of Pre-Columbian Mesoamerican cultures and is an important cash crop with high cultural value in contemporaneous indigenous populations of Guatemala. Despite the increasing attention to native bees as pollinators of cucurbit crops, little is known about the diversity of bees that visit or pollinate these crops in many regions. Based on collections from 11 observational plots of C. pepo established in five localities and maintained by the local community across the Cloud Forest Corridor in Guatemala, we documented 27 bee species belonging to 14 genera in Apidae and Halictidae as floral visitors. Species composition was significantly different among plots and among localities; however, honey bees (Apis mellifera Linnaeus, 1758) (Apidae: Apini) and the stingless bee Partamona bilineata (Say, 1837) (Apidae: Meliponini) were the most abundant flower visitors in all plots and localities, accounting up to 80% of the total number of visits. Two species of squash bees were recorded, Peponapis apiculata (Cresson, 1878) and P. limitaris (Cockerell, 1906) (Apidae: Eucerini), but they were rare (3.4% of total number of specimens) across all plots and localities. Based on pollinator exclusion experiments as well as comparisons of fruit weight and seed number and weight, we confirmed the dependence of this crop on insect pollination and the role of honey bees and P. bilineata as main pollinators in the observational plots. Surveys of bees in the surrounding vegetation of the plots indicated a higher diversity (36 species of 28 genera) than in the plots; about 40% of these species are also common visitors of flowers of C. pepo.