The Altena was a Dutch motorcycle and automobile made by NV Haarlemsche Automobiel & Motorrijwielfabriek, based in Haarlem-Heemstede from 1900 to 1906.
The first car built was powered by a 3.5 hp De Dion single-cylinder powerplant. From 1905 models having 8, 10, and 12 hp engines were offered.
The company was declared bankrupt in 1906 but a few cars were advertised into 1907.
It is estimated that some 40 or 50 cars were made.
G. Marshall Naul, "Altena", in G.N. Georgano, ed., The Complete Encyclopedia of Motorcars 1885-1968 (New York: E.P. Dutton and Co., 1974), pp.38.