Ti3C2Tx, which is a novel two-dimensional (2D) material, has received enormous interest in the field of sensor technology due to its large surface area, excellent electrical conductivity, and abundant active surface sites. In recent years, several Ti3C2Tx-based gases and humidity sensors have been developed and reported. In this review, we focus on the latest applications of Ti3C2Tx-based nanomaterials in gas and humidity sensors. First, the synthesis of Ti3C2Tx from the dangerous fluorine-containing etching process to the safe fluorine-free preparation method was discussed, and the structures of the Ti3C2Tx controlled by different delamination methods were also outlined. Subsequently, the functionalization of pristine Ti3C2Tx and composite strategies for enhancing its gas and humidity sensing performance were reviewed. In addition, the gas and humidity sensing mechanisms of sensors based on Ti3C2Tx were also summarized. Finally, the challenges and opportunities for the use of Ti3C2Tx gas and humidity sensors were discussed to provide guidance on the promising potential of Ti3C2Tx in this field.