Prior research suggests that social relations may play a role in explaining individual differences in cognitive functioning in older adulthood. In particular, early life maternal relationship quality (MRQ) has been shown to be a strong predictor of later-life socioemotional outcomes and may also contribute to later-life cognitive outcomes. The current study aimed to examine longitudinal associations between retrospective early life MRQ and later-life episodic memory directly and indirectly through socioemotional pathways. Three waves of data spanning 6 years of the Health and Retirement Study were used (T1: 2008, T2: 2012, T3: 2014; n = 5,263, M[subscript age] = 69.31, SD = 10.75 at T1). A longitudinal mediation model tested the direct and indirect effects of retrospectively reported MRQ at T1 on T2 memory and latent change in memory from T2 to T3 through depressive symptoms, social network size, and loneliness at T2. Analyses revealed that better MRQ at T1 was associated with less loneliness and fewer depressive symptoms at T2, and in turn, each was independently associated with less decline in memory from T2 to T3. Overall, findings suggest an enduring effect of early life social experiences on later-life cognitive functioning through socioemotional pathways. These findings further highlight the necessity of taking an integrative and life course perspective when examining the relationship between social relations and cognition.