<jats:title>Abstract</jats:title> <jats:p>Polycystic ovary syndrome (PCOS) is one of the most common reproductive endocrine disorders in women and despite this, diagnostic challenges, delayed diagnosis, and less-than-optimal treatment regimens plague the condition. The International PCOS network, consisting of geographically diverse international experts in PCOS as well as consumers, engaged in a multi-year international evidence-based guideline development process that was jointly sponsored by the European Society for Human Reproduction and Embryology (ESHRE) and the American Society of Reproductive Medicine (ASRM). The guideline was published in 2018 and endorsed by more than 40 international societies involved in PCOS. Translation of this evidence-based guideline to medical practice and consumer groups remains a priority. However, there remain many challenges to both understanding the diagnosis and treatment of PCOS. Evidence suggests that both clinicians and consumers are not satisfied with the timeliness of diagnosis and treatment options. This review summarizes the important findings for diagnosis and treatment from the guidelines and expands on recent developments in the literature since its publication. Special attention to diagnosis at the ends of the reproductive spectrum are discussed and remaining areas of controversy are noted. Additionally, the review highlights some of the remaining challenges in the understanding and management of PCOS to help guide clinicians and investigators in this perplexing condition.</jats:p>