Jasmonic acid (JA) plays a crucial role in plant fertility and defense responses. It exerts an inhibitory effect on plant growth when applied exogenously. This effect seems to be somehow related to a negative regulation of cell cycle progression in the meristematic tissues. In this report, we focus on the molecular events that occur during JA-induced G2 arrest. We demonstrate that JA prevents the accumulation of B-type cyclin-dependent kinases and the expression of cyclin B1;1, which are both essential for the initiation of mitosis. This feature suggests the existence of an early G2 checkpoint that is affected by JA.