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A series of high entropy rare earth zirconate ceramics, (5A 0.2) 2 Zr 2 O 7 , with single- or dual-phase structures were synthesized using the solid-state reaction method. The cations at the A site varied in terms of average ionic radius R A , atomic mass M A , radius (size) disorder δ R , and mass disorder δ M. Our results demonstrate that increasing the structural disorder degree promotes the transition from an ordered pyrochlore structure to a defective fluorite structure, and leads to poor sintering resistance. The structural disorder degree of the high entropy zirconates could be increased by decreasing the ionic radius ratio R A /R Zr , increasing the size disorder δ R and introducing Ce4+ at the A site. Meanwhile, large size disorder leads to strong partitioning of rare earth ions and deviation of the lattice constant from the predicted value. The presence of Ce4+ ions at A site could significantly increase the structural disorder degree and promote the sintering process, and the underlying mechanisms are proposed and discussed. [ABSTRACT FROM AUTHOR]