The Outstanding Referee program was instituted in 2008 to recognize scientists who have been exceptionally helpful in assessing manuscripts for publication in the APS journals. By means of the program, APS expresses its appreciation to all referees, whose efforts in peer review not only keep the standards of the journals at a high level, but in many cases also help authors to improve the quality and readability of their articles – even those that are not published by APS. In 2023, 153 Outstanding Referees were selected. Our Editors select the honorees based on the quality, number, and timeliness of their reports, without regard for membership in the APS, country of origin, or field of research. Referees are rewarded for their work carried out since 1978, the earliest year for which we have accurate data on referee reports returned. The decisions are difficult and there are many excellent referees who are still to be recognized.