This study examines dyadic reports of marital quality and loneliness over a two-year period among 932 older married couples resident in Ireland. Data from the first two waves of The Irish Longitudinal Study on Ageing (2009–2013) were analyzed to determine whether husbands’ and wives’ marital quality and loneliness at baseline predicted both spouses’ loneliness 2 years later. Two-wave lagged models tested the cognitive perspective on loneliness, the induction hypothesis, and actor–partner interdependence. Results indicated that perceptions of negative marital quality at baseline were related with greater loneliness 2 years later, supporting the cognitive perspective. Further, both spouses’ reports of loneliness at baseline were related with loneliness 2 years later, supporting the induction hypothesis. Partners’ reports of marital quality were not related with future loneliness, failing to support actor–partner interdependence. I discuss the implications of these findings for theory, practice, and future research concerning intimate relationships and loneliness in later life.