The coconut mite, Aceria guerreronis Keifer (Acari: Eriophyidae), is a major pest of coconut plantations. In Brazil, the control of A. guerreronis, when accomplished, is heavily dependent on applications of conventional acaricides, which further increases the risks associated with pest resistance, hazards to human health and environmental contamination. Therefore, the development of alternatives to the chemical control concerns outlined above is urgently needed. Here, we assessed the composition, toxicity and repellent activities of cottonseed oil to A. guerreronis and its naturally occurring predator Typhlodromus ornatus Denmark & Muma (Acari: Phytoseiidae). Our results revealed that the major compounds in cottonseed oil were linoleic and oleic acids, which have been shown to be bioactive against pests. Concentration-mortality bioassays revealed that A. guerreronis (LC₅₀ = 0.65 µL/cm²) was more susceptible to cottonseed oil than its predator (LC₅₀= 5.11 µL/cm²). Similarly, as demonstrated for the conventional acaricides (i.e., abamectin, azadirachtin, espirodiclofen, and fenpyroximate), cottonseed oil was shown to repel A. guerreronis and its predator. Overall, our findings support the use of cottonseed oil as a desirable tool to be integrated in management programs aimed at controlling A. guerreronis.