We provide a theoretical framework for studying mate search and selection based on a two-sided matching model. Guided by the model, we study dating behavior using data from an experimental dating market, where we generate random matching of subjects and create random variation in the number of potential partners. Male selectivity is invariant to group size, while female selectivity is strongly increasing in group size. This difference implies that the female net utility function of dating is more concave in the number of dates. We also report the valuation of various attributes by men and women; in accordance with the common stereotype, females put greater weight on intelligence relative to males, while males put relatively greater weight on physical appearance. Further, we find that males are less attracted to females with intelligence or ambition greater than their own.