This investigation used a repeated-measures diary methodology to examine associations between humor styles used in the context of dating relationships and relationship satisfaction over time. Over a period of three weeks, undergraduate students (N = 136) completed seven online questionnaires that assessed their relationship satisfaction and dissatisfaction and their use of humor styles with their dating partners over the previous three days. This study represents a departure from previous cross-sectional designs that focus on between-person correlations. Results from the within-person level (i.e., changes within individuals over time), as well as the between-persons level are reported. For some humor styles, within-person findings mirrored between-person findings. For example, affiliative humor use at both levels was positively associated with relationship satisfaction. However, other humor styles revealed different effects at the two levels of analysis. For instance, aggressive humor was negatively associated with relationship satisfaction at the between- but not the within-persons level. A significant cross-level interaction was also found. A strong negative association between daily self-defeating humor and relationship satisfaction was found only for individuals who used high levels of this humor style overall. In contrast, no within-person association was found for those who rarely used this type of humor.