The phase diagram in the subsolidus for the system Dy2O3-ZrO2 has been established. The areas of existence of the high temperature solid solutions based on ZrO2 and Dy2O3 were determined using the precision lattice parameter method. At low temperature, long-range ordering occured in the Dy2O3-rich region (>50 mol% Dy2O3) and two hexagonal compounds of an M7O11.5- and M7O11-type were found. The first of these compounds is formed at about 55 mol% Dy2O3 and possesses a very narrow homogeneity range. At approximately 1750° C this compound undergoes a transformation into cubic solid solutions of fluorite and C-type. The second is formed within the Dy2O3 concentration range between ~65 and 90 mol% Dy2O3. Above 1700° C the hexagonal compound Dy6ZrO11 undergoes a transformation into a cubic solid solution of C-type.