In Kenya, girls tend to lag behind boys when it comes to completing a secondary education. The purpose of this study was to establish the role of principals in the promotion of girl-child education. The objective of the study was to establish the use of education policies by principals in promoting girl-child education. The study employed descriptive survey design. The study population consisted of 38 Principals, 38 Director of Studies (DOS), 2 Sub-County Quality Assurance and Standard Officers (SQASO), 38 Board of Governors (BOG) chair persons and 2010 form four girls. Saturated sampling technique was used to select 35 principals, 35 DOS and 2 SQASO. Simple random sampling technique was used to sample 335 girls. Questionnaires and interview schedule were used to collect data. Validity of the instruments was determined by experts in the department. A pilot study was conducted in 3 schools to establish the reliability of the instruments. Quantitative data was analyzed by use of descriptive statistics, that is, ANOVA. Qualitative data was transcribed and analyzed in emergent themes and sub themes on an on-going process. However, ANOVA revealed that there was a significant difference in the mean responses in principals' use of Education-policies. The findings of this study will help educational administrators in developing better approaches in promoting girl-child education.