Richard Lyons (killed 14 June 1381) was a wealthy medieval English merchant and financier.
He was of illegitimate birth but became a successful, if somewhat corrupt, merchant, a member of the Vintners' Company of the City of London. He was elected an Alderman for the Broad Street ward in 1374 and elected Sheriff of London for 1375.
He was appointed Warden of the Mint and a Privy Councillor under the ageing Edward III. Together with William Latimer, 4th Baron Latimer he acquired such an unsavoury reputation for financial fraud and high interest moneylending that the two men were impeached by the 1376 Good Parliament. This was the first instance of impeachment in law and both men were found guilty. Lyons was imprisoned in the Tower of London and lost his office at the Mint and his position as an Alderman.
Thanks to the helpful influence of John of Gaunt however, he was later released and in 1380 was elected Member of Parliament for Essex.
On 14 June 1381 he was killed and beheaded in the City of London by Wat Tyler and his followers during the Peasants' Revolt. Froissart the chronicler attributed his murder in part to the fact that Wat Tyler had served Lyons on military service in the past and had been badly treated by him. Lyons' head was afterwards carried round the city on a pole.