i-MAX phases are quaternary variants of the nanolaminated MAX phases, with additional in-plane ordering of the M atoms. The combination of in-plane and out-of-plane ordering potentially gives rise to complex magnetic behaviour. The i-MAX phase (Mn2/3Sc1/3)2GaC has been synthesized in epitaxial thin film form on three different substrates, SiC-4H(001), MgO(111) and Al2O3(0001), by magnetron sputtering using elemental targets. Structural characterization by x-ray scattering and scanning transmission electron microscopy confirms the phase on all three substrates, although the highest crystal quality is obtained on SiC-4H(001). Highresolution images reveal the distinctive i-MAX structure, which is orthorhombic of space group Cmcm. Magnetic characterization reveals that the ground state is most likely antiferromagnetic. This confirms previous theoretical calculations which predicted an antiferromagnetic ground state and establishes the (Mn2/3Sc1/3)2GaC i-MAX phase as a potential candidate for antiferromagnetic spintronic applications.