Abstarct: Complex-valued harmonic functions that are univalent and sense-preserving in the unit disk ∆ can be written in the form f = h+ ¯ g, where h and g are analytic in ∆. We give univalence criteria and sufficient coefficient conditions for normalized harmonic functions that are starlike. These coefficient conditions are also shown to be necessary when h has negative and g has positive coefficients. These lead to extreme points and distortion bounds.