--- - |2+ Abstract Objective We examined differences between the oldest known longitudinally followed cohort of extremely low birth weight survivors (ELBW; < 1,000 grams) and normal birth weight (NBW; > 2,500 grams) control participants on shyness and sociability, as well as conflicted shyness in adulthood across nearly a decade from their 20s to 30s. Method 100 ELBW survivors and 88 NBW control participants self‐reported on shyness and sociability using the Cheek and Buss (1981; Cheek, 1983) shyness and sociability scale. Participants also self‐reported on their relationship status. A composite measure of conflicted shyness was also computed (i.e., the product of shyness and sociability). Results We found that, in their 30s, ELBW survivors reported higher shyness, but similar levels of sociability and conflicted shyness compared to controls. However, the ELBW group exhibited a greater decrease in conflicted shyness than NBW controls from their 20s to their 30s. Greater decreases in conflicted shyness in both groups were associated with being male, as well as with changes in relationship status such as finding a partner or getting married. Conclusions Relatively higher shyness among ELBW survivors in adulthood suggests that stressful pre‐ and early postnatal environments may have lasting effects on personality development. However, later social influences such as relationship status may attenuate some types of shyness in adulthood. - Journal of Personality, EarlyView.