Twenty one English Premier League academy football players gave self-ratings of mental toughness two times during the competitive season. Two senior academy coaches also rated the player’s levels of mental toughness using the same scale. Three important findings emerged: first, both player and coach ratings of mental toughness were found to be highly stable over a three-month period. Second, the players’ self-ratings of mental toughness were found to be significantly higher than the ratings of one of the two senior coaches. Finally, there were very low levels of agreement between the two coaches, and between coach and player ratings of mental toughness. These results suggest that even amongst elite level professional soccer coaches, there are considerable differences in interpreting the behaviors and attributes of mentally tough performers.