William Bell Allen (1812 – 5 December 1869) was an Irish-born Australian politician.
He was the son of farmer William Allen and Mary Bell.
In 1841 the family migrated to Sydney, where Allen established a soap and candle business.
By the 1860s he was producing 300 tons of soap a year and exporting to New Zealand.
In 1860 he was elected to the New South Wales Legislative Assembly for Williams, serving until his defeat in 1864.