The influence of the strain rate on the embrittlement of hot isostatically pressed powder metallurgy (PM) Ni₃Al alloys with boron additions has been studied at temperatures between 623–773 K. Tensile testing has been carried out in air at strain rates in the range of 10⁻⁵ to 10⁻¹ s⁻¹. The influence of powder particle size on ductility loss has also been investigated. Results indicate that high elongations to failure are achieved when the intermetallic is tested at the highest strain rate, namely 8×10⁻¹ s⁻¹ but no ductility is observed when tests are carried out within a low strain rate range. This effect is explained in terms of a reduction of oxygen-induced embrittlement when strain rate is higher than oxygen diffusion rate at the crack tip. On the other hand, the decrease in the initial particle size of the intermetallic produces the same effect on ductility as the increase in the strain rate. A microstructure of fine particles in PM Ni₃Al reduces the oxygen embrittlement.