Background Exclusive breastfeeding (EBF) is one of the most cost‐effective, healthpromoting, and disease‐preventing intervention and has been referred to as the cornerstone of child survival. Many mothers however discontinue EBF before the end of six months recommended by World Health Organization (WHO) some due to psychosocial issues. Breast feeding self‐efficacy scale‐short form (BSES‐SF), has been used to establish mothers’ self‐efficacy towards breastfeeding by computing breast feeding self‐efficacy (BSE) scores. These scores have been used globally to predict EBF duration. Internationally accepted tools can be used to compare data across countries. Such tools however need to be translated into local languages for different countries and set‐ups. Objectives The aim of the study was to translate and validate the English BSES‐SF into Kiswahili the national laguage in Kenya. Methods The study was a pilot study within the main cluster randomized longitudinal study. Pregnant women at 37 weeks gestation were randomly placed into, intervention (n=21) and comparison (n=21) groups. The BSES‐SF questionnaire was used to collect data on BSE at baseline and another questionnaire used to collect socioeconomic data. Mothers in the intervention were educated on the importance of exclusive breastfeeding (EBF) and skills required while those in the comparison group went through usual care provided at the health facility. Nutrition education was tailored to promoting maternal BSE. Results The translated BSES‐SF was found to be easy to understand, it showed good consistency and semantic validity. Predictive validity was demonstrated through significant mean differences between the groups. The intervention group had higher EBF rates at 6 weeks post‐partum (χ2=6.170, p=0.013). The Cronbach’s alpha coefficient for the Kiswahili version of the BSES‐SF was 0.91 with a mean score of 60.95 (SD ±10.36), an item mean of 4.354. Conclusion The Kiswahili version of the BSES‐SF is a valid and reliable tool and it has utility in breastfeeding promotion.