Sunflower (Helianthus annuus L.), as an allogamous and entomophilous species, plays a dual role in agroecosystems: it serves as a host that supports diverse insect populations, including pests, while simultaneously providing essential resources that sustain pollinators and natural enemies. Understanding this balance is key factor for sustainable crop management. This study was conducted in Cuautitlán Izcalli, State of Mexico, to analyze the population dynamics of diurnal insect visitors to sunflower. Over a 79-day monitoring period, 2986 individuals from 20 species were recorded. Hemiptera was the most abundant order, dominated by Aphididae (>1600 individuals), alongside other significant pests such as Sphenarium purpurascens Charpentier (Orthoptera: Pyrgomorphidae) and Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae). Importantly, sunflower also attracted a wide range of beneficial insects. The most frequent natural enemies were Hippodamia convergens Guérin-Méneville (Coleoptera: Coccinellidae), a key predator of aphids, while Apis mellifera L. (Hymenoptera: Apidae) represented the dominant pollinator species. Population peaks occurred mainly in September, coinciding with favorable environmental conditions and the onset of flowering, which enhanced both pest and beneficial insect activity. These results highlight sunflower’s ecological importance not only as a host of major pest species but also as a critical reservoir for pollinators and natural enemies. Recognizing this dual function is fundamental for integrated pest management strategies that seek to reduce pesticide use and strengthen ecosystem services in sunflower-based systems.