Time management for educational leaders has remained highly relevant to scholars, policymakers and practitioners. We analyzed survey responses from 98 public high school principals to examine the congruency between average total hours they worked per week against the sum total of the average hours worked per week in each of five distinct categories of leadership tasks. The observed congruence was 0.32, while Cohen’s kappa coefficient was 0.10. Female principals tended to underreport, and male principals tended to overreport, total work time. Principals with doctorate degrees exhibited higher congruence than those without, and overreporting was inversely related to highest degree. Principals in charge of large teaching staffs were more likely than their counterparts to be congruent and less likely to overreport total work time. Self-report appears to be an inaccurate method to measure time use among high school principals. If time use is a key component of the quality of principal leadership, more detailed and robust techniques for collecting time use data should be utilized in future studies.