Previous research has shown that heritability is important in the stability of psychopathic personality traits (PPT) during development; however, previous research has not yet examined the genetic and environmental influences on the growth and development of PPT. The present study examined the extent that genetic and environmental effects influence level and change in PPT using a latent growth curve model. PPT were assessed using self- and caregiver reports (9-10 years, 11-14 years, 15-18 years, N=1,441 twins). Our findings indicated significant growth across age. Specifically, when utilizing caregiver reports, we observed a negative slope indicating a reduction in these traits whereas, the slope was positive when examining these traits using youth self-reports, suggesting an increase in PPT. For caregiver ratings of PPT, the intercept variance due to genetic effects was 95% and 94% for self-reports, suggesting that the stability in PPT is primarily explained by genetic factors. Change in PPT was equally influenced by genetic (47%) and non-shared environmental (53%) effects using caregiver reports; whereas, change in PPT using self-reports was primarily explained by genetic influences (84%). Our findings on the developmental stability and change of PPT demonstrate that genetic influences are important for both the level and change in PPT.