It is the first time that The Mail on Sunday will carry advertising for Lidl, although the retailer has previously run ads in sister title the Daily Mail.
The supermarket chain will carry ad spots on a weekly basis, advertising its various offers.
The deal was secured by Jill Ratcliffe, sales executive in The Mail on Sunday's new-business team.
The newspaper, which has carried ads for Tesco, Sainsbury's, Asda and Morrisons in its Sunday supplements, has earmarked retail as a key area for new-business growth.
The title's new-business team, which was set up 12 months ago and is headed by Vanessa Jeffery, is made up of Ratcliffe, Georgina Holt, sales executive who works across fashion and beauty, and James Brook, sales executive who works on corporate business.