The structure of NaZnSiO3OH, synthesized hydrothermally by reaction of Na2ZnSiO4 and NaOH, has been determined from single-crystal X-ray and powder neutron diffraction data (orthorhombic, space group P2(1)2(1)2(1), a = 7.6872(2) Angstrom, b = 9.3899(2) Angstrom, c = 5.155(1) Angstrom, Z = 4). The structure has a framework constructed from ZnO4 and SiO3OH tetrahedra with bridging and trigonal oxygen atoms. Channels formed from eight-membered rings of tetrahedra house the sodium ions and are also partially blocked by moderately strongly hydrogen bonded OH groups.