Crystals of (NaLa2)NaPtO6 were grown in an acidic ("wet") NaOH flux. (NaLa2)NaPtO6 forms in a 2H-perovskite related structure type and contains mixed cation (Na/La) occupancy on the A-site. The crystal was a rhombohedral obverse-reverse twin, and it crystallizes in the space group R (3) over barc (hexagonal setting) with lattice parameters of a = 9.5031(2) Angstrom and c = 11.4625(5) Angstrom. (NaLa2)NaPtO6 is the first example of an m = 0, n = 1 (A(3)A'BO6) member of the A(3n+3m)A'nB3m+nO9m+6n family of oxides where either a lanthanide or a sodium cation occupies the A-site.