Background Despite the availability of highly efficacious treatments, many individuals with anxiety disorders never receive adequate treatment. Alexithymic deficits, such as difficulties in recognizing feelings and focusing on emotional experiences, may contribute to low rates of help seeking. Methods Multiple Internet-based strategies (announcements of anxiety disorder websites, postings in online self-help forums, notices in anxiety chat rooms) were used to recruit a sample of 312 participants with chronic and clinically relevant anxiety symptoms. Those who had never received professional treatment (n = 49) were compared to those with current or previous treatment (n = 263) with regard to alexithymia, anxiety, depression and health-related quality of life. Results Logistic regression analysis revealed that the strongest predictor for belonging to the never treated group was the externally oriented thinking facet of alexithymia. In addition, substantially more participants in the never treated group (49%) were considered high-alexithymic (20-item Toronto Alexithymia Scale total score ≥61) compared to the treated group (35%). Conclusions The main finding was a strong relationship between the externally oriented thinking facet of alexithymia and the non-use of professional help for anxiety. Internet-based programs could be a promising first step in supporting this group of people to overcome their anxiety.