The purpose of this descriptive study was to determine if business leadership practices by Texas public school principals have an impact on principals' campus student achievement in mathematics and reading, as measured by TAKS scores. The survey instrument was the Leadership Assessment Instrument (LAI), developed by Warren Bennis in 1989. The survey instrument was electronically distributed to a sample of 300 public school principals in Texas. Of the 300, 140 principals completed and returned the survey, for a response rate of 47%. The Statistical Package for the Social Sciences (SPSS), version 16.0, was used for the analysis of data, which included descriptive statistics, analysis of variance, and regression. In addition, reliability for the LAI was also calculated. The LAI consists of the following five categories of effective business practices: focused drive, emotional intelligence, building trust, conceptual thinking, and systems thinking. No significant relationships were found between principals' use of LAI elements and student achievement in mathematics and reading. However, the lack of significant relationships between the business model as used in public schools and student achievement reveals that current models of principal preparation programs do not result in school leaders who are adequately prepared to increase student achievement. Further research is recommended as public school leaders continue to seek alternative strategies and innovative practices to improve student achievement.