Gucciardi et al. (2009) suggest that mental toughness is more a function of environment than domains, and as such, mental toughness is potentially important in any environment that requires performance setting, challenges, and adversities. Due to vital importance of mental toughness in sports and particularly in soccer, this paper focused on the comparison of sport mental toughness levels of soccer officials with their age group, education level, refereeing category and sports experience years. Mental toughness was checked by Sports Mental Toughness Questionnaire (SMTQ). The SMTQ was applied to soccer officials (159 licensed referees) who all were registered to the Turkish Football Federation (TFF). The sample consisted of 146 male subjects, mean age was 29.10 years (SD = 7.54, range = 19-54) and 13 female subjects mean age was 22.82 years (SD = 4.71, range = 19-27). To determine the difference of Sport Mental Toughness level among soccer referees One-Way ANOVA was used for normal distribution and Scheffé Test was used for determining the differences across groups with through SPSS Package 21.0 and the significant level was set at 0.05. The findings of this research paper showed that there were significant differences between soccer officials' three sub-factors (confidence--constancy--control) of mental toughness and their officiating experience years. This could be attributed to the fact that 15 and above years experienced officials were mentally tougher than those with 0-5 years' experience and those with 6-10 years' experience. There were not any significant differences between other variables (refereeing categories, education levels and age groups) of soccer officials and their mental toughness levels.