Machiavellianism is an antisocial interpersonal style involving the use of manipulative, deceptive, and coercive behaviors in the pursuit of self-interest. Although widely studied as a "dark" personality trait in adults, relatively little is known about the developmental correlates of Machiavellian tendencies earlier in life. The present study addressed this knowledge gap by examining associations between Machiavellian behavior and three theoretically relevant social-emotional domains-prosocial emotions, emotion recognition skills, and self-control--in a community sample of 7- and 11-year-old Canadian children (N = 300, 50% female). Of particular interest was the extent to which individual differences in social-emotional capacities were uniquely associated with Machiavellian behavior after controlling for aggression, a relatively well-studied antisocial behavior in childhood. Parents reported on children's Machiavellian behavior and aggression. Social-emotional correlates were assessed via parent and child reports, behavioral tasks, and physiological assessments. Machiavellian behavior and aggression were similarly associated with lower parent-reported prosocial emotions and self-control. Machiavellian (but not aggressive) behavior was associated with lower child-reported guilt (a prosocial emotion), higher resting skin conductance levels (reflecting a general tendency for higher arousal), and better anger recognition. Semipartial correlational analyses indicated that these patterns of association with Machiavellian behaviors held independent of aggression. These findings indicate that, by middle childhood, Machiavellian behavior constitutes a distinct form of antisocial conduct that is associated with a unique social-emotional risk profile.