Background: Adolescence is a high-risk period to fall into the trap of addiction. Meanwhile, having sufficient awareness forces a person to interpret and analyze health threatening factors. This study aimed to determine the relationship between health literacy and susceptibility to addiction in adolescents in the west of Tehran.
Methods: This descriptive-correlational study was performed on 265 senior high school students in west of Tehran in 2021. The subjects were recruited by cluster random sampling. The data was collected on line by the Addiction Susceptibility Questionnaire (ASQ-AV), and Health Literacy Measure for Adolescents (HELMA) and were summarized by frequency distribution, mean, and standard deviation and analyzed using Pearson correlation coefficient, independent t-test, and analysis of variance, in SPSS software version 16. The significance level was set at 0.05. 
Results: Most subjects (56.4%) were female. The mean score of health literacy was 65.31 ± 21.15. Among the subscales of health literacy, “calculation” with the mean score of 68.96 ±35.89 and “utilization” with 61.29 ±25.05 had the highest and lowest mean scores, respectively. The mean score of addiction susceptibility was 25.3±30.05, and among its subscales, “showing off” with the mean score of 33.09 ±32.64 and,  “family dissatisfaction” with 19.75 ±35.47 had the highest and lowest mean scores, respectively. Health literacy and its dimensions had a negative correlation with addiction susceptibility (p<0.001).
Conclusion: According to the findings, it is recommended to use appropriate strategies to increase adolescent health literacy by health service providers, school officials, school health nurses and also teachers. The results of this study can be used as a source for further research in the field of addiction and health literacy in adolescents.