Qualitative data on Thai views of male and female sexuality and sexual behavior are examined in light of hypotheses that have emerged from an evolutionary perspective. The data were derived through focus group discussions and individual in-depth interviews. In particular, we examined how Thai married adults consider men's and women's sexual natures to differ, what men and women seek in a long-term mate, and views of spouse's extramarital sexual activities. In a number of key respects Thai views conform to standard evolutionary predictions. The analysis also illustrates how qualitative research techniques can generate useful data for assessing these predictions.