Metal halide scintillators are described. More particularly, the scintillators include Tl and/or In-based ternary metal halides, such as those of the formulas A2BX4 and AB2X5, wherein A is an alkali metal, such as Li, Na, K, Rb, Cs or any combination thereof; B is an alkali earth metal, such as Be, Mg, Ca, Sr, Ba or any combination thereof; X is a halide, such as Cl, Br, I, F or any combination thereof; some or all of A has been replaced by Tl and/or In, and some or all of B has been replaced by another dopant, such as Eu, Ce, Tb, Yb, and Pr. Radiation detectors comprising the metal halide scintillators are also described.