c. 64) was an act of the Parliament of the United Kingdom that consolidated enactments relating to mentally ill offenders in England and Wales.

Leave to bring in the Criminal Lunatics Bill to the House of Commons was granted to J. T. Hibbert MP and the Home Secretary, Sir William Harcourt MP on 19 June 1884.

[1] The bill had its first reading in the House of Commons on 19 June 1884, presented by J. T. Hibbert MP.

[2] The bill had its third reading in the House of Lords on 8 August 1884 and passed, with amendments.

[2] The amended bill was considered and agreed to by the House of Commons on 8 August 1884.