Background: Concussion nondisclosure and poor management after a concussion are a concern in Irish collegiate sports. How athletes perceive concussions and appraise their own concussion may affect their decisions and behaviors after a suspected concussion. However, this has yet to be examined in an Irish context. This study aimed to (1) establish concussion perceptions and associated anxiety in Irish collegiate athletes; (2) examine how sex, concussion, and mood disorder history influenced their perceptions; and (3) investigate factors associated with higher anxiety perceptions. Hypothesis: Irish collegiate athletes will display negative concussion perceptions and anxiety related to concussion, especially in female athletes and those without a concussion history. Study Design: Cross-sectional study. Level of Evidence: Level 3. Methods: Irish collegiate athletes [n = 268 (141 women,127 men), mean age = 21.5 ± 2.2 years] from high-risk sports completed a survey including the Perceptions of Concussion Inventory for Athletes (PCI-A), demographics, diagnosed concussion history, self-reported mood disorder history, and a concussion knowledge assessment. Differences in concussion perceptions by sex, concussion history, mood disorder history were examined using Mann-Whitney U tests, and factors associated with anxiety-related concussion perceptions were identified using multivariate logistic regression. Results: Over half (53.0%, n = 142) of participants reported concerns regarding concussion. The thoughts of sustaining a concussion made participants feel upset (63.4%, n = 170), fearful (47.7%, n = 128), and anxious (35.1%, n = 94). Women reported significantly higher anxiety (P < 0.01, r = 0.23), effects (P = 0.04, r = 0.12), and clarity (P = 0.01, r = 0.16) perception scores. Participants with a diagnosed concussion history displayed greater symptom variability perception scores (P = 0.04, r = 0.12), but lower anxiety (P = 0.03, r = 0.13) and treatment (P < 0.01, r = 0.19) beliefs on the PCI-A. No differences were observed for those with a history of a mood disorder (P > 0.05). A significant multivariate model was established (χ² = 55.44, P < 0.01), with female sex [odds ratio (OR) = 1.53], concussion history (OR = 0.63), effects (OR = 1.31), and treatment (OR = 1.15) subscales associated with greater anxiety. Conclusion: Concerns about sustaining a concussion are prevalent in Irish collegiate athletes. Women displayed more negative perceptions and those with a concussion history displayed fewer perceived benefits of treatment. Clinical Relevance: The findings support the need for concussion awareness campaigns to provide accurate concussion information to mitigate anxiety-related concussion perceptions and injury belief misconceptions. © 2022 The Author(s).