Ba 1-x Dy x Fe 12-y Zn y O 19 (x = 0 -0.1 and y = 0 -1) hexaferrites were produced by the sol-gel auto -combustion technique. In the XRD analyses of all samples, BaFe 12 O 19 phase was observed as the pure state. ZnFe 2 O 4 begins to form at x = 0.02 and y = 0.2 and peak intensities increases with the substution of Dy 3+ and Zn 2+ cations for the samples sintered at 900 degrees C and 1100 degrees C. As the temperature increases to 1300 degrees C, peaks belonging to BaFe 12 O 19 phase were disappeared and transformed into Ba 3 Fe 26 O 41 and BaZn 1.2 Fe 16.8 O 27 phases at x = 0.06 and y = 0.6. Crystallite size decreased with increasing Dy 3+ and Zn 2+ substitutions for the samples sintered at 900 degrees C and 1100 degrees C. The smallest crystallite size obtained at 900 degrees C, x = 0.06 and y = 0.6. As the amount of substitution elements increase, saturation magnetization (M s ) and remenance magnetization (M r ) values decreased due to the formation of paramagnetic spinel ZnFe 2 O 4 phase for the samples sintered at 900 degrees C and 1100 degrees C. The highest M r value of 36.1 emu/g was obtained for the pure samples sintered at 1300 degrees C. It decreased sharply to 18.9 emu/g (about 50%) with the substitution of Dy 3+ and Zn 2+ cations at x = 0.02 and y = 0.2. Dy 3+ and Zn 2+ substituted hexaferrites sintered at 900 degrees C (x = 0.06 and y = 0.6) exhibited the highest H c value of 4.84 kOe.