测地线效应（英语：Geodetic Effect）或测地线进动（英语：Geodetic Precession）是指在广义相对论预言下引力场的时空曲率对处于其中的具有自转角动量的测试质量的运动状态所产生的影响，这种影响造成了测试质量的自转角动量在引力场内沿测地线的进动。这种效应在今天成为了广义相对论的一种实验验证方法，并且已经由美国国家航空航天局于2004年发射的科学探测卫星“引力探测器B”在观测中证实。

The geodetic effect (also known as geodetic precession, de Sitter precession or de Sitter effect) represents the effect of the curvature of spacetime, predicted by general relativity, on a vector carried along with an orbiting body. For example, the vector could be the angular momentum of a gyroscope orbiting the Earth, as carried out by the Gravity Probe B experiment. The geodetic effect was first predicted by Willem de Sitter in 1916, who provided relativistic corrections to the Earth–Moon system's motion. De Sitter's work was extended in 1918 by Jan Schouten and in 1920 by Adriaan Fokker. It can also be applied to a particular secular precession of astronomical orbits, equivalent to the rotation of the Laplace–Runge–Lenz vector.