IntroductionMigrant women consistently rate their care during labour and birth more negatively than non-migrant women, due to communication difficulties, lack of familiarity with how care is provided, and discrimination and prejudicial staff attitudes. They also report being left alone, feeling fearful, unsafe and unsupported, and have poorer birth outcomes than non-migrant women. Community-based doulas (CBDs) are bilingual women from migrant communities who are trained in childbirth and labour support, and who facilitate communication between woman-partner-staff during childbirth. This study protocol describes the design, rationale and methods of a randomised controlled trial that aims to evaluate the effectiveness of CBD support for improving the intrapartum care experiences and postnatal well-being of migrant women giving birth in Sweden.Methods and analysisA randomised controlled trial. From six antenatal care clinics in Stockholm, Sweden, we aim to recruit 200 pregnant Somali, Arabic, Polish, Russian and Tigrinya-speaking women who cannot communicate fluently in Swedish, are 18 years or older and with no contraindications for vaginal birth. In addition to standard labour support, women are randomised to CBD support (n=100) or no such support during labour (n=100). Trained CBDs meet with women once or twice before the birth, provide emotional, physical and communication support to women throughout labour and birth in hospital, and then meet with women once or twice after the birth. Women’s ratings of the intrapartum care experiences and postnatal well-being are assessed at 6–8 weeks after the birth using selected questions from the Migrant Friendly Maternity Care Questionnaire and by the Edinburgh Postnatal Depression Scale. The intervention group will be compared with the control group using intention-to-treat analyses. ORs and 95% CIs will be estimated and adjustments made if key participant characteristics differ between trial arms.Ethics and disseminationThe study was approved by the Regional Ethical Review Board in Stockholm (approval number: 2018/12 - 31/2).Trial registration numberNCT03461640; Pre-results.