Background: Few studies have addressed on the role of parent–child connectedness (PCC) on adolescents' risk for suicidal ideation from a longitudinal, developmental perspective. Aim: This study examined PCC during adolescence and risk of suicidal ideation into adulthood among a nationally representative sample of American adolescents. Method: The study includes 13,234 adolescents aged 11–18 from the National Longitudinal Study of Adolescent to Adult Health (Add Health) who were surveyed during adolescence (1994–1995) and then again in early adulthood (2008–2009). Multinomial logistic regression estimated the association between PCC during adolescence and having ideation during the adolescence period only, in adulthood only, and in both adolescence and adulthood as compared with those without suicidal ideation. Results: After adjusting for depressive symptoms and other parent and adolescent characteristics, adolescents in two-parent households who reported higher PCC during adolescence had lower relative risk of having ideation during adolescence alone and in both adolescence and adulthood. In mother-only households, higher mother connectedness was also associated with decreased risk of having adolescent ideation. Conclusion: PCC is an important modifiable target for the prevention of suicidal ideation from adolescence into adulthood.