We address design, implementation, and characterization of semiconductor strain gauges as stage displacement sensors with small footprint for piezo-driven nanopositioners in differential actuation mode. The results indicate that in this actuation mode, a differential sensing strategy provides much better accuracy than the conventional non-differential schemes. The proposed differential sensor has a large sensitivity of $4.4\frac{V}{{\mu {\text{m}}}},$ 3σ-resolution of 2.4 nm, and bandwidth of 4 kHz.