3. c. 79) was an Act passed by the Parliament of Great Britain in 1799, as part of measures by Pitt the Younger to suppress republican opposition.

Printers were closely regulated, because one of the main problems in the Government's view was that seditious pamphlets were widely circulated and untraceable.

In the end any Masonic lodge existing at the time of passage of the Act was exempted, so long as they maintained a list of members and supplied it to the magistrates.

This provision was relaxed in the Printer's Imprint Act 1961 to exclude simple documents like greeting cards or invoice books.

[5] At that time, some unscrupulous customers apparently instructed printers to omit their imprints, and then refused to pay their bills on the grounds that the work had been conducted illegally.