The magnetic properties of the Heulser alloy Cu2VAl were comprehensively investigated. A broad maximum at low temperature in both zero-field-cooled magnetization and the real part of the linear ac susceptibilities as well as a clear irreversibility between the zero-field-cooled and field-cooled magnetization curves were detected. The absence of the second harmonic ac susceptibility and a negative peak observed in the third harmonic ac susceptibility indicate its spin glass ground state. Fitting of the temperature dependences of the linear ac susceptibilities with different frequencies to the Vogel–Fulcher model and the critical slowing down power law confirms the spin glass nature of the detected magnetic behavior at low temperature in the Heusler alloy Cu2VAl.