Phenotypic plasticity in response to environmental change is a common phenomenon, yet is poorly understood at the genetic and molecular level. Aphids exhibit a reproductive plasticity whereby seasonal changes result in asexual or sexual reproduction. To investigate the genetic basis of this reproductive plasticity, we assessed the meiosis and cell cycle gene repertoire in the genome of the pea aphid, Acyrthosiphon pisum. Aphids possess meiotic recombination genes and G1-to-S phase transition regulatory genes in gene copy numbers similar to other metazoans. However, mitotic and meiotic regulatory genes have duplicated, and several paralogues exhibit differential expression between reproductive morphs. Together, this suggests that cell cycle plasticity may be important in the evolution and mechanism of aphid reproductive plasticity.