A severe outbreak of the pine processionary moth (PPM), Thaumetopoea wilkinsoni, began in 1998 vegetation period and lasted to the end of 2002 vegetation period in a brutian pine (Pinus brutia) stand in Isparta region of Turkey. In this study, the effect of PPM defoliation degree (control, moderate and high) was investigated on radial growth of individual trees in a pure and young brutian pine plantation. Comparisons of average annual radial growth for defoliation classes were made for pre-outbreak (1992 to 1997), out-break (1998 to 2003) and post-outbreak (2004 to 2009). Tree ring chronologies of control group were used to estimate the growth potentials. Growth recovery began as soon as the defoliation ended and annual radial increments of damaged trees were parallel level of control group. Average annual pre-outbreak and post-outbreak growth rates did differ for all of the three classes using paired t-tests. The difference between pre-outbreak and post-outbreak was significant for all defoliation classes. Thus, growth recovery from 2004 to 2009 was apparently not strongly related to class of defoliation. According to analysis of covariance, difference in y-intercept was significant but not for slope. When testing for differences among defoliation classes, a no significant difference in slope was detected.