Electrical resistivity ρ, magnetization M, and specific heat measurements are reported on La 1−x Pr x Ti 2 Al 20 for x = 0.11, 0.22, 0.32, 0.43, 0.51, and 1. The ρ(T) data for all samples monotonically decrease on cooling from 300 K to 3 K. The magnetic susceptibility χ(T) data approach constants on cooling for T < 10 K, which is the behavior of a van Vleck paramagnet. The Curie-Weiss behavior of χ(T) for 50 < T < 300 K gives effective magnetic moments of 3.4-3.8 µ B /Pr, which are close to 3.58 µ B for a free Pr 3+ ion. The paramagnetic Curie temperatures are nearly constant at −40 K, irrespective of the value of x. The magnetic specific heat divided by temperature, C m /T , for x = 1 shows a cusp-type anomaly at T Q = 2.1 K due to the ferroquadrupole (FQ) order. With decreasing x, it becomes broadened and shifts to the lower temperature at 0.8 K for x = 0.32, indicating the survival of the FQ order. For x ≤ 0.22, C m /T increases as −lnT on cooling from 0.7 K to 0.37 K. Once the FQ order collapses, the non-Fermi liquid behavior appears for x ≤ 0.22, suggesting manifestation of single-site quadrupole Kondo effect.