The bill received unanimous support in the House.
A wild herd of about 100 horses believed to be descendants of the Spanish mustangs that arrived in the 1500s live along the coastal fringe of Currituck County. Another 120 or so inhabit a coastal area in Carteret County.
The horses are popular with visitors to the region and are a common sight on the beaches.
The idea of naming the Spanish mustang as state horse came from students at Currituck County elementary school.
The Corolla Wild Horse Fund, formed in 1989 to heighten awareness of the horses in Currituck County, says they have survived nearly 500 years of fierce nor'easters and hurricanes.
"[They] are an integral part of what draws hundreds of thousands of visitors to the northern beaches every year. Nowhere else can you see wild Mustangs walking along the beach and grazing among beach homes."