This cluster-randomized controlled trial examined the effect of couple-based health education on male partners’ knowledge and attitude towards maternity waiting homes (MWH) in rural Ethiopia. Sixteen clusters and 320 couples were randomly assigned to intervention group (receiving group health education, home visits and print health messages alongside usual care) or control group (receiving usual care). The Chi-square test was used to estimate statistical differences, and the difference-in-differences model was used to estimate the effect of the intervention. The generalized linear regression model was used to determine the odds of outcomes between the groups. Statistical significance was set at p < 0.05, with a 95% CI. There were no significant differences in baseline characteristics between the control and intervention groups. The net effect of the intervention on improving knowledge about MWHs, and attitude towards MWHs were 35.6% and 36.2%, respectively. The participants in the intervention group were 5.5 times more likely to have good knowledge about MWH (AOR 5.55, 95% CI 3.37–9.14) and 5.6 times more likely to have a favorable attitude towards MWH (AOR 5.61, 95% CI 3.45–9.10) compared to their counterparts. Health education provided to couples significantly improved male partners’ knowledge and attitude towards MWHs in rural Ethiopia.Trial registration: ClinicalTrials.gov Identifier: NCT05015023.