The study was on the level of administrative effectiveness of Heads of Academic Departments in Nigerian universities and the significant difference (if any) in administrative effectiveness of male and female Heads of Academic Departments. One research question and one hypothesis were raised / formulated to direct the investigation. Out of 1520 Heads of Academic Departments in all 36 public universities in Nigeria, 1326 academic staff in nine universities were selected from 362 Departments in nine universities for the study. The results of investigation revealed that the administrative effectiveness of Heads of Departments in Nigerian universities was high. Since there was no significant difference in the area of sex, it was recommended among others that gender should not be a hindrance in the appointment of Heads of Departments.