Plant diversification mitigates colonization by herbivorous insects in agricultural systems. Tomato and sweet corn generate raw material, for industrial processing, with outstanding production in Goiás state, Brazil. Yet, little is known about the potential of sweet corn as a companion plant for sucking insects, and natural enemies, in tomato plants. We collected pests and natural enemies in tomato (pre-flowering stage) plants under three treatments: isolated tomato plants (T1), tomato plants with sweet corn in the border (T2), and tomato plants with polyculture (garlic, lettuce, and squash) in the border (T3). The insects were collected by yellow sticky traps. Dalbulus maidis (29.52%), Frankliniella schultzei (23.90%), F. occidentalis (18.72%) and Myzus persicae (15.20%) corresponded to 87.34% of the total insects collected. Tomato plants cultivated with sweet corn on the border had lower infestation of the thrips, F. schultzei as well as the aphid M. persicae. The number of D. maidis and F. occidentalis adults did not change according to the treatments. Diabrotica speciosa and Astylus variegatus were more collected in tomato plants with adjacent sweet corn. Predators and parasitoids represented only 6.62% of the total abundance. Cycloneda sanguinea and parasitoids were more collected in tomato plants with polyculture (T3). Tomato with sweet corn or polyculture favored the abundance of the predator Sphaerophoria scripta. Considerations around the control of insect pests and the sustenance of natural enemies in tomato plants, with sweet corn acting as a companion plant, in the pre-flowering stage of that Solanaceae, are demonstrated.