This chapter presents a study on the linearization of transconductance amplifiers using active back-gate input signal injection. The technique addresses the inherent large-signal nonlinearity in Metal-Oxide-Semiconductor (MOS) transconductors in differential pair configurations. The nonlinearity, precipitated by the square-law behavior of MOSFETs, is mitigated by actively injecting the input signal into the isolated back gate provided by the employed fully depleted silicon-on-insulator (FD-SOI) CMOS technology. The approach uses an auxiliary amplifier to balance the transconductance contributions from both the front and back gates, resulting in an overall linear transconductance function. The efficacy of this method is demonstrated through theoretical analysis and a practical design example in a Continuous-Time Sigma Delta Modulator. This technique retains key benefits such as the high input impedance in open-loop Operational Transconductance Amplifiers (OTAs), making it a robust solution for high-performance and power-efficient analog circuit designs.