This review specifies how individuals’ relationship power (actor power) and their partners’ power (partner power) influence distinct behaviors in close relationships. High-power actors can promote their own needs, whereas low-power actors must inhibit their needs or enact aggression or manipulation to fight for their needs. Actors must also accommodate the needs of high-power partners but can neglect or may feel obliged to protect low-power partners. Structural power asymmetries outside relationships prompt ideologies that shape perceptions, expectations, and subsequent behavioral responses to power within relationships. Using gender ideologies to illustrate, competitive ideologies (hostile sexism) motivate aggression by those who fight for power or prompt inhibition by those who cede power. Cooperative ideologies (benevolent sexism) divide power, generating accommodation of partners’ needs in some domains and neglect in others. We emphasize the need to consider actor and partner power, relationship and structural power, power symmetries and asymmetries, and competitive and cooperative ideologies.