The increase in the cost of building materials as well as the need in reducing the use of natural resources, such as soils, requires the creation of composite materials. These composites can replace natural soils or have superior engineering properties. The addition of cement as stabilization technique is widely discussed in the literature, as well as the addition of fibers in the soil. The presence of the fibers modifies the behavior of the soils generating a more ductile, more cohesive and slightly more compressible material. On the other hand, the soil treated with cement shows a significant increase in strength and stiffness properties. In the case of the simultaneous inclusion of cement and fibers, the literature shows that a high fiber content gives greater post-cracking resistance to the soil and a smaller cracking size. This research evaluated the influence of cement and Polyethylene terephthalate (PET) fibers in the shear strength of a lateritic fine-grained soil. Direct shear tests were conducted with cement-treated soils in the contents of 2, 6 and 10% (in relation to soil dry mass). Samples were compacted using Standard Proctor tests at optimum water content for each cement percentage addition and degree of compaction of 95%. In order to evaluated the influence of fibers, direct shear tests were conducted on the lowest strength of cement addition (corresponding to 2%). Fibers, taken from disposable bottles having lengths of 10, 15, 20 and 30 mm and width of 1.5 mm, were randomly added to the soil in percentages of 0.75; 1.0; 1.5 and 2.0% (in relation to the dry mass). The results showed that the higher the percentage of cement increment, the greater was the increase in the shear strength of the soil. In the case of soil-cement-fiber, it was verified that the inclusion of 1.0% of fibers of 15 mm in length presented the highest values ​​of atritive interface and, in relation to the cohesive intercept, the highest values ​​obtained were the percentage of 2.0% and length of 20 mm. In general, evaluating the behavior of the fibers, those with longer lengths lead to a higher shear strenght of the composite.