To promote sustainable consumption, predictors of individuals’ intentions need to be understood. Focusing on the example of collaborative consumption, we look at facilitating and inhibiting factors in a preregistered correlational study (N = 378). We hypothesized the Value-Identity-Personal norm (VIP) model to explain variance in sharing intention. In addition, we expected sharing intentions to be linked to attitudes about (de-)ownership. We also hypothesized self-extension into an object to be a barrier to sharing this object. The results supported all hypotheses: The VIP model and de-ownership orientation were related to sharing intentions. Moreover, self-extension into a car was significantly higher among subsamples of car owners than car sharers. Exploratory findings show that the value-intention link predicted by the VIP can be found for biospheric as well as altruistic values if sharing intentions are assessed with items framed to match these respective values. We discuss implications for attempts to promote sustainable consumption.