This study investigated the Planning, Supervision and Quality of Instructional Leadership of Girls' Day Secondary Schools in Kaduna State. The research design adopted was a survey design. The independent variables were the respondents which include principals, teachers, students, parents and government officials while dependent variable includes planning, supervision and quality of instructional leadership of girls' day secondary schools. This study was conducted in Girls' Day Secondary Schools across Kaduna State. A Multiple sampling technique was adopted to sample six hundred and forty-eight (648) respondents consisting of 300 males and 348 females. Three hypotheses guided the study. The instrument for data collection was the questionnaire which was duly validated and found to be reliable. Analysis of variance (ANOVA) was used to test the null hypotheses at 0.05 level of significance. Results showed that there was a significant difference among the respondents on the planning of Girls' Day Secondary Schools in Kaduna State, there was a significant difference among the respondents on the supervision of Girls' Day Secondary Schools in Kaduna State and there was a significant difference among the respondents on the quality of instructional leadership of Girls' Day Secondary Schools in Kaduna State. It was recommended that the Kaduna State Government should ensure adequate planning and running of Girls' Day Secondary Schools by putting machinery on ground in terms of resources needed by the schools. The schools should be adequately supervised by the ministry of education officials to ensure compliance with government directives on quality education.