Structural, social, and cultural conditions of modern societies generate strain for all women, which produces negative effect. Women tend to internalize negative effect as guilt and hurt rather than externalize it as anger directed at a target. This results in a situation analogous to overcontrolled personality, and results in low overall rates of deviance punctuated by occasional instances of extreme violence. The conditions found in long-term abusive relationships and pre- or postpartum environments are more likely to produce this result, but the theory is not limited to explaining female homicide in these settings. Most theory and research in criminology focus on explaining criminal behavior by men, and explanations of criminal behavior by women have been adapted from the male-oriented findings. The consistency of the pattern of homicides by women, as well as the differences from the patterns of homicides by men, suggests the need for a separate theoretical explanation of female homicidal behavior. The article includes: (1) An Overview of the New Theory; (2) "Baseline" Stress and Negative Affect in the Lives of Women; (3) Blockage of Women's Coping Mechanisms; (4) Overcontrolled Personality; and (5) Situational Stresses. Footnotes, references