Thermal expansion measurements have been carried out using dilatometry on the (RE)BaCuO system in the temperature range 300β1100 K. The peak in the thermal expansion coefficient (Ξ±) at 890 K presages the high-temperature orthorhombic-to-tetragonal phase transition in YBa2βCu3βO7βΞ΄β. The thermal expansion behaviours of YBa2βCu3βO7βΞ΄β, Y2βBaCuO5β, NdBa2βCu3βO7βΞ΄ and Nd4βBa2βCu2βO10β, which are the constituent phases of melt-processed high-Jcβ superconducting ceramics, are compared. The relevance of dilatometric studies at high temperature to such multiphase ceramic bodies is discussed