The present study examined three types of personality change and continuity (mean‐level, individual‐level, and rank‐order stability) over the 2‐year period in a nationally representative longitudinal sample of Estonian adolescents (N = 876) aged 12–18. According to the Reliable Change Index, 82.1% of adolescents maintained the same level on any given personality trait measured by the NEO Five‐Factorial Inventory (NEO‐FFI) indicating that the individual‐level continuity of adolescents did not differ compared to young adults. A reliable increase was found in Openness. Across the five dimensions, the average test–retest correlations were 0.51, 0.56 and 0.67, and the computed biennial stability values were 0.80, 0.83 and 0.89 for age groups 12 → 14, 14 → 16 and 16 → 18 years, respectively. Neither intelligence nor school performance moderated the differential continuity. Copyright © 2006 John Wiley & Sons, Ltd.