The multi-point borehole extensometer is an instrument designed to measure displacements and deformations along the axis of a borehole, enabling distributed monitoring of movements in soil, rock, or structures. The instrument consists of a reference head installed at the borehole collar and a series of anchors positioned at known depths, connected to the head by rigid rods (stainless steel) or flexible rods (fiberglass) housed inside protective sheaths that ensure free movement. Variations in distance between the anchors and the reference head allow accurate determination of the magnitude, distribution, and time evolution of deformations along the monitored profile. The instrument can be manufactured with multiple measuring points, allowing detailed analysis of soil or structural behavior at depth, and is available in both manual and automated versions with electrical transducers and data acquisition systems.