Bulk metallic glasses are considered as potential materials for engineering application due to the absence of long-range periodicity. The ability of material to be cast into amorphous phase is defined by the term called glass forming ability (GFA). In the present paper, GFA of Zr-, Hf- and Ti-based metallic glass have been studied based on well-established γ* parameter. The γ* parameter has been calculated for reported binary, ternary, quaternary and quinary Zr-, Hf- and Ti-based systems. The γ* parameter increases with Zr, Hf and Ti content in Zr–Cu–Ni, Hf–Cu–Ni and Ti–Cu–Ni systems validating the confidence of parameter. These findings are well matched with existing literature in which 50–60 at.% Zr, Hf and Ti form amorphous phase in Zr–Cu–Ni, Hf–Cu–Ni and Ti–Cu–Ni systems, respectively. Hence, applicability of γ* parameter has been discussed in context to Zr-, Hf-, and Ti-based systems. The result shows that γ* is an effective thermodynamic parameter to define the GFA in binary, ternary, quaternary and quinary Zr-, Hf- and Ti-based systems.