Q-RepEx is an open-source Python tool, designed to perform replica exchange empirical valence bond (REMD-EVB) simulations using the Q6 simulation package . The concept is adapted from Ref. , and the source code is available on GitHub at the following link: , under the GNU General Public License version 2 (GPLv2), as well as on Zenodo, DOI: 10.5281/zenodo.7331764. The REMD-EVB procedure parallelizes the EVB-FEP/US calculations and thus increases and accelerates the sampling of the simulations, thus improving the statistics obtained. The main functionality of Q-RepEx is the unconditional exchange of simulation conditions for a series of EVB/FEP-US simulations.