Background <p>Anxiety disorders are among the most prevalent mental health issues faced by young adults, who experience the highest lifetime prevalence of these conditions. Despite the increasing rates of anxiety disorders, mental health service utilization within this demographic remains notably low. This study aims to analyze the factors influencing mental health service utilization among young adults with anxiety disorders, distinguishing between early young adults (19–29 years) and late young adults (30–39 years), to propose tailored support strategies.</p> Methods <p>Data from the 2021 National Mental Health Survey of Korea, which included 395 adults diagnosed with anxiety disorders, were analyzed. Complex sample logistic regression was used to assess how sociodemographic characteristics, health behaviors, and comorbid mental health issues impact service utilization.</p> Results <p>Among early young adults, higher education (odds ratio [OR] = 6.57), being married (OR = 7.02), and suicidal thoughts (OR = 29.42) were significantly associated with increased mental health service utilization. For late young adults, suicidal thoughts (OR = 10.79) and post-traumatic stress disorder (OR = 15.87) were significant predictors of higher service use, while alcohol use disorder was associated with lower service utilization (OR = 0.07).</p> Conclusions <p>This study highlights the need to prioritize support for early young adults with lower education, single status, and suicidal thoughts, as well as late young adults with alcohol use disorder, post-traumatic stress disorder, or suicidal thoughts. Implementing these strategies may enhance mental health management and improve the overall quality of life for young adults.</p>