Anxiety is a prevalent mental health condition in the Western world. Adults experiencing anxiety have been found to use a range of herbal medicines to manage anxiety symptoms. Aim: This study aimed to test a theoretical model based on the theory of planned behaviour that predicted the intention to use herbal medicines for anxiety symptoms, and to identify individual predictors of intention. Methods: An online survey was conducted with Australian adults who experienced anxiety and used herbal medicines (N = 400). A two-step approach to structural equation modelling was used to test a path model predicting the intention to use herbal medicines. Results: The model was found to be well-fitting. Attitude, subjective norms, control beliefs and severity of anxiety symptoms each significantly positively predicted intention to use herbal medicines for anxiety symptoms explaining 56% of the variance. Conclusions: The results suggest that mental health practitioners and policy makers need to ensure people experiencing anxiety have access to accurate and reliable information about herbal medicines to ensure they can effectively manage anxiety symptoms and safely engage in self-care.