The Tartan Army face Canada in a friendly at Hibs' Easter Road on Wednesday, 22nd March before taking on Slovenia in a World Cup qualifier at Hampden Park on Sunday, 26th March.
And the United duo have been called up by Gordon Strachan.
Dumfries-born Hanley has won 27 caps for his country, scoring once, while Ritchie has scored three goals in 14 international appearances.
The Scotland squad to face Canada and Slovenia is: Craig Gordon (Celtic), David Marshall (Hull City), Allan McGregor (Hull City, on loan at Cardiff City), Ikechi Anya (Derby County), Christophe Berra (Ipswich Town), Grant Hanley (Newcastle United), Russell Martin (Norwich City), Charlie Mulgrew (Blackburn Rovers), Andrew Robertson (Hull City), Kieran Tierney (Celtic), Lee Wallace (Rangers), Stuart Armstrong (Celtic), Barry Bannan (Sheffield Wednesday), Scott Brown (Celtic), Oliver Burke (RB Leipzig), Tom Cairney (Fulham), Darren Fletcher (West Bromwich Albion), James Forrest (Celtic), Ryan Fraser (Bournemouth), James McArthur (Crystal Palace), John McGinn (Hibernian), James Morrison (West Bromwich Albion), Matt Phillips (West Bromwich Albion), Matt Ritchie (Newcastle United), Robert Snodgrass (West Ham United), Steven Fletcher (Sheffield Wednesday), Leigh Griffiths (Celtic), Chris Martin (Derby County, on loan at Fulham), Steven Naismith (Norwich City), Jordan Rhodes (Middlesbrough, on loan at Sheffield Wednesday).
