This study evaluates the permanent deformation behaviour of two Brazilian soils with the addition of buriti fibre (Mauritia flexuosa), a natural fibre abundant in the Brazilian Cerrado. The tests were conducted according to the CEN EN 13286-7:2004 standard, in multiple stages, to verify the occurrence of shakedown. The analysed soils were collected in Piauí (Soil 1) and Mato Grosso do Sul (Soil 2). For Soil 1, the addition of the fibre reduced permanent deformation up to a content of 0.5%, showing reductions of up to 56%, while higher contents exhibited behaviour similar to the natural soil. For Soil 2, which is sandier in nature, the fibre did not reduce the deformation but contributed positively to the occurrence of shakedown. The results indicate the potential of buriti Queryfibre for improving the mechanical performance of fine-grained clayey soils for application in road paving.