μ Orionis (Latinised to Mu Orionis, abbreviated to μ Ori or Mu Ori) is a quadruple star system[6] in the constellation Orion, similar to Mizar and Epsilon Lyrae with combined visual magnitude of 4.13.

Mu Orionis Aa is an A5V dwarf and metallic line star, of effective temperature 8,350 Kelvin, and apparent magnitude of +4.31.

Mu Orionis Aa has 2.1 solar masses, and a radius of 2.9 R☉ and a luminosity 32 times that of the Sun.

Mu Orionis Ba and Bb are F5V dwarfs with 1.4 solar masses and apparent magnitudes of 6.91.

μ Orionis is very close in the sky to the faint planetary nebula Abell 12.