This research purpose was to analyze the relationship between anxiety and mental toughness among athlete students. A quantitative method with correlation design was used in this research. Subjects of this research were one hundred and twenty-eight athlete students. All participant were athlete students at State Senior High School of Sport or namely SMANOR in Sidoarjo, East Java, Indonesia. There were seventy eight male and fifty female. The average age of participants was sixteen and half years old. Data were collected using two instruments: An adapted Sport Anxiety Scale with unfavorable score to measure an anxiety, A mental toughness scales to measure mental toughness. The research result indicates that there was a significant relationship between anxiety and mental toughness with coefficient correlation zero point seventy-five. These results can be interpreted that the higher the level of anxiety, the lower the level of mental toughness is. This is because of anxiety make athlete students have bad feeling and negative emotion that influence their mental toughness.