Background: Cluttering is a fluency disorder characterized by an abnormally fast or irregular speech delivery rate along with disfluencies that are frequent but are not judged to be stuttering. Data on cluttering prevalence in the general population are scarce, as well as its association with psychological well-being indices, such as anxiety, and depressive symptoms., Aims: To estimate cluttering prevalence among undergraduates, as well as its relationship with psychological and well-being indicators., Methods & Procedures: To address these issues, a large sample (n = 1582) of undergraduates completed a questionnaire that provided a lay definition of cluttering and were asked to identify themselves as clutterers (SI-Clut), as well as to indicate the presence of several psychological and mental well-being indices., Outcomes & Results: A total of 276 respondents (23%) self-identified as clutterers (now or in the past), with 55.1% of those being male. Only 56 respondents (3.5% of the total sample; about 21% of SI-Clut) reported having received speech therapy for cluttering. Relative to students self-identifying as non-clutterers, self-identification of cluttering was associated with higher levels of psychosomatic symptoms, depressive symptoms and stress, indicating a tendency toward internalizing psychopathology, along with lower self-esteem, and lower subjective happiness., Conclusions & Implications: The current findings point to the high prevalence of students self-identifying as clutterers, along with a significant link between cluttering and mental distress. Therefore, it is important to increase public awareness of cluttering, its diagnosis and treatment. From the clinical perspective, the elevated levels of somatic complaints, anxiety and depression may represent internalizing psychopathology, associated with more covert rather than overt symptomatology. Such symptom manifestation calls for special attention from the speech-language pathologists providing cluttering therapy, using designated well-being or mental health screening tools. Although data on standard cluttering treatment are limited, it should be customized to the client's unique difficulties. Speech-language pathologists' understanding of cluttering, which includes both speech characteristics as well as psychological and social aspects of well-being, may assist them in implementing effective treatments., What This Paper Adds: What is already known on the subject Cluttering is a fluency disorder characterized by an abnormally fast or irregular speech rate, along with various disfluencies and articulatory imprecision. It may co-occur with other disorders, such as learning disabilities, and attention-deficit/hyperactivity disorder. Data on cluttering prevalence and its association with psychological well-being indices, such as anxiety and depression, are limited. What this paper adds to existing knowledge A total of 276 undergraduates (23%) self-identified as clutterers, of whom 55.1% were males. A total of 56 respondents (3.5% of the total sample, and about 21% of undergraduates self-identified as clutterers) reported having received speech therapy for cluttering. Psychosomatic symptoms, depressive symptoms and stress levels were higher among these students, suggesting a tendency toward internalizing psychopathology, along with a lower sense of self-esteem and subjective happiness. What are the potential or actual clinical implications of this work? The high prevalence of students self-identifying as clutterers, along with the low percentage of respondents who received speech therapy for cluttering, emphasize the need to raise public awareness of the problem, its diagnosis and treatment (Reichel et al., 2010). The association between cluttering and mental distress requires speech-language pathologists to be aware that cluttering may have covert symptomatology, similar to stuttering, which should be addressed in therapy., (© 2023 Royal College of Speech and Language Therapists.)