Neutron scattering includes powerful and versatile techniques for investigating materials under extreme conditions, such as high pressure, high/low temperature, and strong magnetic fields. Due to the unique interaction of neutrons with the atomic nuclei and magnetization, neutron scattering can provide important information about the structure and dynamics of materials. In this talk, I will introduce the advantages of neutron scattering and present recent examples of neutron scattering studies under extreme conditions at the Spallation Neutron Source (SNS) and the High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory. I will highlight a few state-of-the-art sample environments and in-situ capabilities available to the user community. Finally, I will discuss the future of neutron scattering at the Second Target Station (STS) and its opportunities to address grand challenges in materials science using advanced sample environments and performing time-resolved experiments.