The real dielectric constant ϵ' and loss factor tan δ were studied as function of frequency f, temperature T and composition x for a series of samples of BaCo2xZnxFe12-2xO19 hexagonal ferrite system with x = 0.4, 0.8, 1.2, 1.6 and 2 prepared using the usual ceramic technique. The experimental results indicated that ϵ' and tan δ decrease as the frequency increases and temperature decreases. The studied samples showed abnormal dielectric behavior (or relaxation peaks) which were shifted towards higher frequency as the temperature and substitution of Co and Zn ions increase. Increasing the Co and Zn ions substitution for x ≤1.2, ϵ' and tan δ decrease reaching minima while activation energy for dielectric relaxation ED and pre-exponential constant f0 increase reaching maxima at x = 1.2. The behavior was reversed for x > 1.2, where ϵ' and tan δ increase while ED and f0 decrease