There is a large body of knowledge on the restorative potential of public green space, but studies on private gardens are rare. This study was aimed at exploring perceived restorativeness of private gardens and its predictors. In an online survey, 856 respondents rated the perceived restorativeness of private gardens, attached outdoor green spaces and living rooms with green elements. Characteristics of the garden, sociodemographic data, personal characteristics, and the relationship between user and garden were surveyed. Results indicated that the private garden scored highest on perceived restorativeness. A multiple regression analysis explained 52.2% of the variance of the perceived restorativeness of private gardens. The garden–user relationship qualified as the strongest predictor of the restorative potential. We suggest considering the significance of affective bonds in designing restorative private gardens.