This paper analyzes the sources of ambivalence toward political parties and candidates. We propose and test an information-processing theory of ambivalence in which systematic processing is hypothesized to heighten partisan and candidate ambivalence. We show that ambivalence is linked to several dispositional sources of systematic processing, including individuals' information, motivation, and cognitive style. Specifically, we find that ambivalence tends to be greater among the well informed and those who are high in need for cognition while it tends to be lower among those motivated by directional goals. Collectively, our results suggest that levels of partisan and candidate ambivalence are greatest among those most likely to engage in effortful processing of information and that these effects are independent of value conflict. The results further suggest that the effects of effortful processing on ambivalence are moderated by attitude commitment.