Two-dimensional numerical computations were carried out on flow past a heated circular cylinder undergoing vortex-induced vibrations (VIVs). The cylinder was elastically mounted on springs and allowed to oscillate in streamwise and transverse directions. The C++ library in the finite-volume–based OpenFOAM software program was used for the simulations. The solver was modified to consider thermal effects, and an energy equation was added to the existing solver. The flow and thermal characteristics were examined for different values of the reduced velocity (Ur) ranging from 1 to 8. Three different mass ratio (m*) values (i.e., 2.5, 5, and 10) were considered at Reynolds number (Re) = 200. The effects of the Ur and m* values on the cylinder response and frequency ratio were disclosed. Higher oscillation amplitudes, i.e., the synchronous regime, were found to change with a change in the m* value. With a change in the Ur value, different modes of vortex shedding and their effects on the temperature field were examined, corresponding to each value of m*. The heat transfer coefficient of the cylinder undergoing VIVs was found to be higher than that observed for the stationary cylinder at the same Re value. The mean drag coefficient and root-mean-square value of the lift coefficient were also reported with a change in the Ur value for each value of m*. © 2023 by Begell House, Inc.