The invention relates to an attenuated variant of the Rift Valley Fever Virus (RVFV) with mutations in the amino acid sequence coded by segments L, M and S of RVFV RNA; a pharmaceutical or veterinary composition comprising same; an attenuated RVFV variant for use in the prevention of Rift Valley Fever; and a vaccine against Rift Valley Fever comprising the attenuated RVFV variant. Attenuated RVFV variants with the mutations Gly924Ser and Ala303Thr in protein L, and the Pro82Leu substitution in protein NSs, are also included.