In this study, magnesium‐zirconium–substituted M‐type barium hexaferrites BaFe12‐2xMg+xZrxO19 (BFMZO, 0.25 ≤ x ≤ 1.5) nanoparticles were successfully synthesized by sol‐gel autocombustion technique. On one hand, the effects of Mg‐Zr substitution concentration on the magnetic features of doped magnetic nanoparticles were investigated which showed that increasing the doping concentration causes the saturation magnetization to decrease. On the other hand, the influence of the different layer thicknesses (2, 3, and 4 mm) of BFMZO on the microwave absorption was investigated in X‐band frequencies (8‐12 GHz). Absorption results showed that increasing the film thickness from 2 to 3 mm causes microwave absorption to increase. Moreover, the morphological study reveals that aggregation percentage decreased when the substitution concentration increased. Therefore, size, magnetic, and absorption properties are tunable by substitution concentration.