Emerging contaminants (ECs) are substances not included in current environmental regulations that are capable of harming humans and wildlife even at very low concentrations (e.g., in the ng L−1 range). Wastewater or even drinking water can be a threat to human and environmental health when it includes dissolved ECs, despite it complying with local, regional or international water standards. Naturally found in mammals and invertebrates, estrogens are considered ECs because of their undesirable biological effects on humans and other organisms. It has been demonstrated that conventional drinking or wastewater treatment processes cannot sufficiently separate or degrade them from the water. For this reason, advanced oxidation processes (AOPs) have been investigated to reduce estrogen concentrations and estrogenic activity, pursuing the partial or total mineralization of natural and synthetic estrogens. One AOP showing high efficiency is photocatalytic degradation based on semiconducting nanoparticles. The present work summarizes the fundamentals and significant findings on photocatalytic AOPs for the treatment of water contaminated with estrogens using semiconductor nanoparticles from early work to the present day.