In this article, we consider the predefined-time synchronization problem of stochastic memristor-based bidirectional associative memory neural networks (MBAMNNs). First, considering the influence of stochastic disturbance, we propose two new predefined-time theorems. Second, combined with the predefined-time theorem proposed in this article, we design a feedback controller to realize the predefined-time synchronization of MBAMNNs. Then, the sufficient conditions for the predefined-time synchronization of MBAMNNs are obtained based on Ito’s formula and Lyapunov theorem. Finally, the effectiveness of the theorems is verified by numerical simulations.