Adapting the theory of planned behavior to the area of financial choices in family firms, we argue that these choices in family firms are largely affected by family norms, attitude, perceived behavioral control, and behavioral intentions. A time-lagged sample, estimated via structural equation modeling of 118 German family firms, supports a behavioral approach to the study of financing decisions. Specifically, we show that family norms and attitude toward external debt and external equity affect behavioral intention to use the respective financing choices, which in turn affects financing behavior. Perceived behavioral control, however, was shown to negatively affect behavioral intentions to use external equity and was positively related to the use of internal funds. Implications of these capital structure decisions and ideas for future research are discussed.