The duration of the juvenile period (JP) before the seedlings reach the adult phase (AP) and begin flowering is the major impediment for fruit breeding in olive. In this work, the effect of soil solarization on the growth and duration of the JP of olive seedlings was studied. Seedlings obtained from open pollination of ‘Manzanilla de Sevilla’ and from crosses between ‘Arbequina’ × ‘Arbosana’ and ‘Picual’ × ‘Koroneiki’ were tested. Solarization treatment consisted on covering the soil around the trees for 3 years by black plastic film in a split-plot design with the three progenies as the main factor and solarization/not solarization as the secondary factor. Solarization resulted in both higher soil temperature and soil moisture in solarized plots with respect to non-solarized. Significant differences between crosses were found for plant vigor and flowering measurements throughout the experiment. Soil solarization increased trunk diameter and the number of seedlings reaching AP in ‘Manzanilla’ open progeny. A positive effect of solarization on flowering index was also observed in ‘Picual’ × ‘Koroneiki’ progenies. These results suggest that soil solarization may be recommended as a tool for shortening the duration of the JP and thus accelerating the selection process in olive breeding programs.