Couple relationship quality is known to drop significantly across the transition to parenthood (Ahlborg & Strandmark, 2001;Doss, Rhoades, Stanley, & Markman, 2009), yet individual differences in the amount of parent-to-infant talk have rarely been studied in relation to variation in couple relationship quality. Addressing this gap, the current study of 93 first-time parents with 4-month-old infants included multimeasure reports of couple relationship quality from both mothers and fathers and examined associations between couple relationship quality and the home language environment, assessed via the Language Environment Analysis (LENA), when infants were approximately 7 months old. LENA consists of a wearable talk pedometer that records a full day of naturalistic parent-infant talk and is coupled to software that provides automated analysis. Given the covariation between depression and both couple relationship quality and parental infant-directed talk, both maternal and paternal depression were controlled for in all analyses. Results showed that, for mothers of sons, frequency of infant-directed talk was inversely related to couple relationship quality. Consistent with family systems theory, this finding provides partial support for the compensation hypothesis. However, variation in couple relationship quality was unrelated to infant-directed speech in fathers or in mothers of daughters. Together, these findings demonstrate that the gender composition of the parent-infant dyads plays a moderating role on the association between couple relationship quality and parent-infant talk.