The mental health of adult extremely low birth weight (ELBW) (<1000 g) survivors is poorer than their normal birth weight (NBW) peers. An understanding of the modifiable factors that affect this risk could provide targets for intervention. We set out to determine the extent to which a maternal history of mental health problems influenced mental health in ELBW and NBW offspring in adulthood. A total of 85 ELBW and 88 NBW individuals born between 1977 and 1982 in central west Ontario, Canada self-reported on internalizing (depression, anxiety) and externalizing (attention-deficit hyperactivity and antisocial) problems using the Diagnostic and Statistical Manual of Mental Disorders (DSM) scales of the Young Adult Self-Report at ages 22–26 and 30–35. They also reported on their mother’s maternal mental health using the Family History Screen. An interaction was found between birth weight status and maternal history of an anxiety disorder such that ELBW survivors showed a greater increase in internalizing scores than NBW participants at 22–26 (β = 10.27, p = 0.002) and at 30–35 years of age (β = 12.65, p = 0.002). An interaction was also observed between birth weight and maternal history of mood disorder, with higher externalizing scores in ELBW survivors than NBW adults at 22–26 (β = 7.21, p < 0.0001). ELBW adults appear to be more susceptible to the adverse mental health effects of exposure to maternal mood and anxiety disorders than those born at NBW. These links further highlight the importance of detecting and treating mental health problems in the parents of preterm survivors as a means of attempting to reduce the burden of psychopathology in this population.