The effect of temperature on the electrodeposition of copper at overpotentials belonging to the plateau of the limiting diffusion current density and higher was examined by the determination of the average current efficiency of hydrogen evolution and by scanning electron microscopic (SEM) analysis of the morphology of the formed copper deposits. Increasing the temperature of the solution led to a shift of both the beginning and the end of the plateau of the limiting diffusion current density towards lower electrodeposition overpotentials. Also, higher temperatures led to the formation of morphological forms of copper deposits characteristic for electrodeposition of copper at some higher overpotentials. The unexpected trend in the development of copper structures electrodeposited at an overpotential of 800 mV is discussed in terms of the effect of temperature on the viscosity and surface tension of the electroplating solution.