Preterm babies in Malawi are not receiving adequate care, and social norms that undervalue small newborns are an important barrier to improved outcomes. In 2015-2016 the Ministry of Health and Save the Children piloted a campaign, Khanda ndi Mphatso, Lipatseni Mwayi (A Baby is a Gift, Give it a Chance) in two districts. The campaign targeted pregnant women and mothers of preterm babies as well as their male partners and their influencers. The image phase used a “branded” campaign to shift individual attitudes and community norms to increase the value of newborn lives. The tactical phase used an intense community engagement and social mobilisation component to promote specific health behaviours and encourage family and community support. We carried out a mixed-methods evaluation 13 months after implementation began to understand campaign effects. Using a quasi-experimental design, the evaluation compared basic implementation sites, which included campaign materials, mass media, and facility-based approaches, to comprehensive implementation sites, which added community-based activities. Data analysed included 247 quantitative interviews with pregnant women and mothers of preterm babies and 15 focus group discussions. We developed a measure of campaign dosage to explore dose-response, based on reported participation in campaign activities and recall of campaign materials. The intervention provided direction on future facility and community level strategies that are effective in addressing behavioural and social norms that negatively affect care and survival of preterm and low-birth-weight babies. The evaluation showed that the campaign contributed to changes in injunctive norms around the care of newborns, increasing value for LBW and preterm babies, and encouraging social support. Adaptation of the Khanda ndi Mphatso campaign in other districts has the potential to shift social norms around care for newborns in Malawi.