Exploring and understanding magnetism in two-dimensional (2D) van der Waals (vdW) magnetic materials present a promising route for developing high-speed and low-power spintronics devices. Studying their magnetic properties at the nanoscale is challenging due to their low magnetic moment compared to bulk materials and the requirements of highly sensitive magnetic microscopy tools that work over a wide range of experimental conditions (e.g., temperature, magnetic field, and sample geometry). This Perspective reviews the applications of nitrogen-vacancy center (NV) based magnetometry to study magnetism in 2D vdW magnets. The topics discussed include the basics, advantages, challenges, and the usage of NV magnetometry.