Objective: The purpose of this study was to investigate the impact of intolerance of uncertaintyon speech anxiety among pre-service teachers, as well as the mediating effects of achievement motivationin this relationship. Method: A survey was conducted on 328 pre-service teachers using the SpeakerConfidence Self-Rating Scale, Achievement Motivation Scale, Intolerance of Uncertainty Scale. Results:(1) Intolerance of uncertainty was positively correlated with speech anxiety among pre-service teachers;(2) Intolerance of uncertainty indirectly predicted speech anxiety through achievement motivationand the motivation to avoid failure. Conclusion: Intolerance of uncertainty among pre-service teachersinfluences speech anxiety, which is mediated by the motivation to avoid failure and achievementmotivation, in addition to its direct effect.