Background: Complex issues, including a failure to consider the perspectives of people with fertility problems when selecting outcomes, variations in outcome definitions, and outcome reporting bias, make the results of infertility research difficult to interpret. Objectives: To develop a core outcome set to standardise outcome selection, collection, and reporting across future randomized controlled trials and systematic reviews evaluating potential treatments for infertility. Methods: Healthcare professionals, researchers, and people with fertility problems were brought together in an open and transparent process using formal consensus science methods including a three-round Delphi survey (372 participants from 41 countries) and consensus development workshop (30 participants from 27 countries) (1). Results: The core outcome set consists of: (1) viable intrauterine pregnancy confirmed by ultrasound (accounting for singleton, twin, and higher multiple pregnancies); (2) pregnancy loss (accounting for ectopic pregnancy, miscarriage, stillbirth, and termination of pregnancy); (3) live birth; (4) gestational age at delivery; (5) birth weight; (6) neonatal mortality; and (7) major congenital anomaly. Time to pregnancy leading to live birth should be reported when applicable. Conclusions: Embedding the core outcome set within randomized controlled trials and systematic reviews should ensure the comprehensive selection, collection, and reporting of core outcomes. Research funding bodies, the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) statement, and over 80 specialty journals, including Cochrane Gynaecology and Fertility Group, Fertility and Sterility, and Human Reproduction, have committed to implementing this core outcome set.