Sexual conflict arises when the fitness interests of males and females diverge, leading to genes and traits that have antagonistic fitness effects across the sexes. This thesis uses theoretical models to examine the causes and consequences of such conflict, focusing on the roles of population ecology and genetic architecture in shap- ing evolutionary responses to sex-specific selection. Chapter 1 investigates the demographic consequences of selection on males to harm or harass females in order to improve their own mating success. It shows that such male harassment traits readily evolve condition-dependence, whereby individuals in good condition, or of high genetic quality, express more harm. Consequently, intensified sexual conflict can lead high-condition populations to show reduced population size and greater extinction risk, contrary to the commonly held view that individual condition is positively correlated with population viability. Chapter 2 concerns the segregation of sexually antagonistic alleles, genetic variants beneficial to one sex but harmful to the other, in spatially subdivided populations. It shows that a species’ dispersal pattern modulates the evolutionary dynamics of such alleles due to the effects of kin selection. Thus, dispersal ecology can determine which sex is better adapted to its environment, and how much genetic variation is maintained in populations. Finally, Chapter 3 asks how frequently sexually antagonistic alleles arise from sex-specific selection on complex traits (those encoded by many interacting loci). It investigates how antagonism may be resolved through expression modifiers, showing that variation in genetic architecture (such as the number and distribution of fitness effects across trait loci) favours different patterns of sex-specific versus sex-limited gene expression, and that this can drive outbreeding depression in dispersal-limited populations. Together, the chapters of this thesis demonstrate that aspects of trait genetic architecture and a species’ population ecology that have been underappreciated in previous theory, are relevant to the outcomes of sexual conflict.