pH sensing facilitates many substantial aspects of the society such as chemical laboratory analysis, agriculture, or water and soil qualities. However, existing pH sensors have problems and limitations such as fragility, hysteresis, or slow responding time. In this research, a new method utilizing fluorocarbon thin film via fluorine termination and boron‐doped diamond (BDD) solution‐gate field‐effect transistors (SGFETs) for pH sensing is developed for the first time. The fluorocarbon film device demonstrates a high pH sensitivity of 67.4 and 34.9 mV pH−1in acid and alkaline pH regions, respectively. A high pH sensitive boron‐doped diamond solution‐gate field‐effect transistor incorporating fluorocarbon thin film is fabricated for the first time. The device shows high pH sensitivities at 67.4 and 34.9 mV pH−1in acid and alkaline pH regions, respectively. Future research will focus on the effect of film thickness and the response to elevated temperatures.