Extant research provides little evidence about how health literacy, self-efficacy and health locus of control are related to each other in affecting health behaviors. The purposes of this study were to examine the associations among health literacy, self-efficacy and health locus of control and how the three factors are related to health behaviors using data from a national survey of Taiwanese adults. The analysis showed moderate correlations among health literacy, self-efficacy and locus of control, suggesting that they were independent, albeit correlated, factors. Moreover, we found in most cases that health literacy, self-efficacy and locus of control had independent associations with health behaviors. Of the three factors, self-efficacy had the most consistent and positive associations with health behaviors. Our findings suggest that efforts to promote and sustain health behaviors need to focus on improving individuals' emotional states and correcting their faulty self-beliefs and habits of thinking. Health education campaigns and enhancement of literacy skills alone may not achieve the desirable goal of behavioral change.