Arnold is a toy manufacturing company founded in Nuremberg on 4 October 1906 by Karl Arnold. Specialising in tin toys, it also produced boats and doll's houses until the Second World War, when the factory was completely destroyed.

It is best known for launching the Arnold Rapido model train range in 1962 in the 1:160 scale with a track gauge of 9 mm: this was the birth of the N scale.

From 1960 to 1962, production consisted of a range of small "Rapido 200" trains, in 1:200 scale, more toy train than model train.

However, from 1962, the company turned to the production of real model trains and became the reference N production from 1970 onwards. In 1964, the N scale was recognised as the NEM standard and later the "Rapido coupler" was adopted as the European standard for the scale.

In 1995 the firm was bought by Rivarossi and in 2004 by Hornby PLC.