Introduction: Climate change poses health risks to populations, particularly in socioeconomically disadvantaged urban communities with limited adaptive capacity. However, evidence on climate change–related health literacy, defined as individuals’ ability to access, understand, and use information on climate-related health risks, remains limited. This study aimed to assess climate change–related health literacy among adults living in a disadvantaged district of Istanbul and to examine its association with selected demographic characteristics related to vulnerability and adaptation.Methods: A community-based cross-sectional study was conducted between July and September 2025 among adults aged 18–65 years registered with family physicians in Sultanbeyli, Istanbul. Using simple random sampling, 1,182 individuals were contacted, and data from 441 participants were analyzed. Data were collected using a demographic information form and the 24-item Climate Change Health Literacy Scale. Independent samples t-tests and one-way ANOVA were used for analysis.Results: The mean age of participants was 38.7 ± 12.1 years, and 53.3% were female. Most participants (94.6%) had not received formal education on climate change, and social media was the main source of information (65.1%). Only 21.8% reported sufficient knowledge of climate change–related health impacts. The mean total health literacy score was 94.4 ± 14.0, indicating a moderate level of literacy. Higher scores were observed among women, individuals with higher education, and those who regularly followed climate-related news (p < 0.05). No significant differences were found by income or occupation.Discussion: These findings reveal gaps between knowledge and the adoption of protective behaviors in disadvantaged urban communities. Community-based health education initiatives are essential to strengthen adaptive capacity.