Burglars stole cash and jewellery from a house near Langtoft Primary School on Thursday.
A gang used a double glazed door at the side of the house to get in between 9.30am and 12.30pm.
Anyone with information should call Market Deeping Police Station on 101, quoting incident number 220 of July 6.
You can also call Crimestoppers, anonymously, on 0800 555 111.