The term EM1 may refer to:

• Former name of Artemis 1, Exploration Mission-1, a mission for NASA's Orion spacecraft
• Olympus OM-D E-M1, a compact mirrorless interchangeable lens camera
• Korg Electribe EM-1, a digital synthesizer
• EM-1 Microbial Inoculant, first product in the line of effective microorganism supplements
• EM1, a designation for a vacuum tube, of Magic Eye type
• EM-1, The intermediate language used in the Amsterdam Compiler Kit

• British Rail Class 76, or Class EM1, an electric locomotive
• EM-1, a class of Baltimore and Ohio Railroad locomotives
• Elias EM-1, a 1920s prototype US military biplane
• EM1, chassis code for a 1995–2000 Honda Civic coupe
• EM1, a type of Honda E engine used for the Honda Civic during 1980–83
• Honda EM1 e:, an electric scooter introduced in 2023

• EM-1, an experimental British assault rifle, precursor of the EM-2 rifle
• EM1, or Electrician's Mate 1st Class, an enlisted rate in the US Navy and US Coast Guard
• EM1, a category for streaming pupils formerly used in education in Singapore