The bismuth‐doped rare‐earth iron garnets, (R3−x−yBixPby)Fe5O12 (Bi:RIG, R=Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y), were prepared under constant growth conditions to investigate the influence of ionic species on the bismuth‐based growth‐induced uniaxial anisotropy Kgu. The effect of ionic species on growth‐induced anisotropy in Bi:RIG was not consistent with the ionic size model of site ordering. In particular, Bi:SmIG, Bi:EuIG, and Bi:TbIG displayed high growth‐induced anisotropies, up to 331 000 erg/cm3 at room temperature for x≊0.5. The temperature dependence of these Kgu’s was somewhat higher than that of the well studied Bi:YIG. The site ordering of Bi can be modeled by assuming that small, low‐oxygen‐coordination BiO+3−2ww melt complexes have a strong site selectivity for small, high‐oxygen coordination sites at the growth interface.