- Objective: To determine the efficacy and characteristics of psychological or educational eHealth interventions on reducing symptoms of mental illness in parents of preterm or low birthweight infants. Background: Many parents suffer psychological disorders after preterm birth. Computer or mobile application-based interventions are a promising alternative. Methods: We searched seven electronic databases up to January 2020 and included randomised and quasi-randomised controlled trials assessing psychological or educational eHealth interventions in parents of infants born very preterm <32 weeks or with very low birthweight <1500g (primary question), or preterm <37 weeks or with low birthweight <2500g (secondary question). Primary outcomes were measures of depression, anxiety, acute stress disorder or post-traumatic stress disorder. Secondary outcomes included other indicators of mental health, quality of life and intervention characteristics. We had planned random-effects meta-analysis in our protocol (CRD42018105731). Results: Of 9768 records, no study reported our primary outcomes. Three studies showed potential benefits for parental self-efficacy, discharge preparedness, parental satisfaction and family satisfaction with the neonatal intensive care unit. Conclusions: We found scarce evidence on the efficacy of psychological or educational eHealth interventions on reducing mental illness in parents of preterm or low birthweight infants, highlighting the need for more research.