国际地球自转服务（International Earth Rotation Service，IERS）全称为国际地球自转和参考系服务（International Earth Rotation and Reference Systems Service)。是一家提供全球时间和参考系标准的机构。

The International Earth Rotation and Reference Systems Service (IERS), formerly the International Earth Rotation Service, is the body responsible for maintaining global time and reference frame standards, notably through its Earth Orientation Parameter (EOP) and International Celestial Reference System (ICRS) groups.