Social order is possible only if individuals forgo the narrow pursuit of self-interest for the greater good. For over a century, social scientists have argued that sympathy mitigates self-interest and recent empirical work supports this claim. Much less is known about why actors experience sympathy in the first place, particularly in fleeting interactions with strangers, where cooperation is especially uncertain. We argue that perceived interdependence increases sympathy towards strangers. Results from our first study, a vignette experiment, support this claim and suggests a situational solution to social dilemmas. Meanwhile, previous work points to two strong individual-level predictors of cooperation: generalized trust and social values. In Study Two we address the intersection of situational and individual-level explanations to ask: does situational sympathy mediate these individual-level predictors of cooperation? Results from the second study, a laboratory experiment, support our hypotheses that sympathy mediates the generalized trust-cooperation link and the relationship between social values and cooperation. The paper concludes with a discussion of limitations of the present work and directions for future research. (Contains 2 figures, 3 tables and 12 footnotes.)