Understanding the role of negative emotionality in the development of executive functioning (EF) and language skills can help identify developmental windows that may provide promising opportunities for intervention. In addition, because EF and language are both heritable, intergenerational transmission patterns are important to consider. The prospective parent-offspring adoption design used in the Early Growth and Development Study (EGDS) provides a unique opportunity to examine the intergenerational transmission of EF and language skills. Using data from EGDS (n = 561 children adopted around the time of birth), we examined the role of heritable influences and negative emotionality in toddlerhood (age 9 to 27 months) and childhood (age 4.5 to 7 years) on child EF and language skills at age 7. There was continuity in EF from age 27 months to 7 years, and in language ability from age 27 months to 7 years, with no cross-lagged effects between child EF and language ability. Negative emotionality at age 9 months predicted lower EF and lower language abilities at age 7, and growth in negative emotionality from age 4.5 years to 7 years predicted lower child EF at age 7. Overall, findings suggest that lower negative emotionality at age 9 months is associated with higher toddler and child EF and language skills, and that preventing growth in negative emotionality from age 4.5 years to 7 years may lead to improvements in child EF.