The Space Environment Monitor (SEM) is a suite of instruments onboard the GOES satellite series. The objective of the SEM package is to measure solar radiation in the X-ray and Extreme Ultraviolet (EUV) region, the in-situ magnetic field, and the energetic particle environment at geosynchronous orbit. This collection contains L0 data from GOES 8-12, provided as monthly binary files and L0 data from GOES 13-15, provided as daily binary and ASCII files. The SEM instrument on GOES 8-12 is composed of four sensors: SEM/EPS (Energetic Particle Sensor), SEM/HEPAD (High Energy Proton and Alpha Particles Detector), SEM/MAG (Magnetometer), and SEM/XRS (X-Ray Sensor). The GOES 13-15 SEM suite added these 3 sensors: SEM/EUVS (Extreme Ultraviolet Sensor), SEM/MAGED (Magnetospheric Electron Detector), and SEM/MAGPD (Magnetospheric Proton Detector). On GOES 13-15, the historical EPS sensor was renamed EPEAD (Electron, Proton, and Alpha Detector) and the term EPS now refers to the suite of particle detectors (EPEAD, MAGED, MAGPD). Combined these sensors provide magnetic field, energetic particle, and solar x-ray and EUV data. The magnetometer (MAG) measures the magnitude and direction of the magnetic field. The energetic particle detectors (EPS, HEPAD, EPEAD, MAGED, MAGPD, and MAGED) measure a spectrum of electron, proton, and alpha-particle fluxes caused by solar activity and galactic cosmic rays. The solar x-ray sensor (XRS) measures solar X-ray fluxes for the wavelength bands of 0.05-.4 nm (short channel) and .1 to .8 nm (long channel). The extreme ultraviolet sensor (EUVS) measures the EUV in 5 bands (A-E) spanning wavelengths 5-127 nm. The temporal period of record (POR) for this collection extends from April 1994 to March 2020. The data were produced by the NOAA/NESDIS Office of Satellite and Product Operations (OSPO) and archived by NOAA's Comprehensive Large Array-Data Stewardship System (CLASS). To access this data, contact NCEI for distribution and ordering instructions.