The development of few-mode fiber (FMF) has found numerous interesting applications in optical sensing. Given the remarkable capabilities of FMF, optical sensors of novel functionalities can be deployed. Here, we review the progress on state-of-the-art technology for FMF-based optical sensing. In particular, we focus on utilizing FMF for multi-parameter and absorption-based sensing. Additionally, we summarize the trials of using FMF as a compromise between single-mode fiber (SMF) and multimode fiber (MMF) to develop optical sensors of higher signal-to-noise ratio (SNR) and spatial resolution. A final discussion on the main limitations of FMF-based sensors along with prospects for further research are presented.