Magnetic properties and magnetocaloric effect (MCE) of the HoAgGa compound are investigated by magnetization and heat capacity measurements. A giant reversible MCE was observed around TC = 7.2 K. The maximum values of magnetic entropy change and adiabatic temperature are found to be 16 J kg−1 K−1 and 6 K, respectively, with a refrigerant capacity value of 262 J kg−1 for field change of 5 T. These magnetocaloric parameters also remain large for a wide range of temperature above TC. The large MCE as well as no hysteresis loss make HoAgGa an attractive candidate for low temperature magnetic refrigerant.