Using knowledge about plant–insect interactions in a crop protection perspective is a pre-requisite to promote the development of novel pest management strategies. Enhancing plant natural defenses has been described as a promising way to improve the management of pests. In cotton, plant topping (cutting off the top of the plant) for inducing such defenses has been proposed as a promising tool for integrated pest management. The main objective of this study was to explore the effect of cotton topping on the performance of the cotton aphid, Aphis gosypii, under greenhouse conditions. The effect of plant topping was evaluated on topped and on neighbor non-topped plants. Results showed that cotton topping disturbed A. gossypii aphids not only on the topped plant but also on neighbor non-topped plants. The population of aphids grew slower in the topped compared to the control treatment and lower abundances of aphids were found in the topped treatment up to a distance of 100 cm to the topped plant. When an individual nymph was confined in a clip-cage, the production of winged adults after 15 days of confinement was higher in the topped compared to the control treatment. This difference decreased as the distance to the topped plant increased. In conclusion, our study proves that cotton topping mediates plant-pest interactions on the focal and neighbor plants. We discuss how cotton topping is a promising technique that could be used as part of an integrated pest management program, particularly for smallholders in West Africa, for controlling aphid infestations.