To determine the prevalence and correlates of help-seeking behaviors for insomnia in Hong Kong Chinese middle-aged adults and their offspring. A total of 2231 middle-aged adults (54.2% females, mean age 45.8 years) and 2186 children and adolescents (51.9% females, mean age 13.4 years) completed a questionnaire on insomnia symptoms, daytime functioning, health condition and treatments sought for insomnia. A total of 40% of adults and 10% of children and adolescents with insomnia reported having sought treatment for insomnia. Conventional Western medicine was the commonly preferred treatment in 33.3% of adults and 13.3% of children and adolescents who sought help for insomnia, while a higher proportion of individuals with insomnia (34.5% of adults and 26.7% of children and adolescents) sought help from complementary and alternative medicine (CAM) therapies. Female gender (odds ratio [OR] [95% confidence interval, CI] = 2.14 [1.01–4.53]), higher family income (≥15,000 HKD/month) (OR [95% CI] = 3.15 [1.27–6.34]), severity of insomnia (Insomnia Severity Index ≥14) (OR [95% CI] = 2.12 [1.10–4.12]), chronic medications (OR [95% CI] = 4.71 [2.27–9.79]), and psychiatric disorders (OR [95% CI] = 2.83 [1.01–7.96]) were associated with help-seeking behaviors in adults. Presence of morning headache was associated with help-seeking behaviors in children and adolescents (OR [95% CI] = 8.66 [1.72–43.70]). It is uncommon for Hong Kong Chinese to seek help for insomnia, despite the high prevalence of insomnia. The significant unmet need argues for timely intervention to promote sleep-health literacy and to enhance the awareness and accessibility of evidence-based treatment for insomnia.