Chelsea forward Eniola Aluko, who is the top English goalscorer in Super League 1 this season, has again been overlooked for the friendly fixtures.
Aluko, 29, and Duggan, 25, were both left out of Sampson's previous two squads, for the Euro 2017 qualifiers against Serbia, Estonia and Belgium.
England qualified top of their group.
Chelsea midfielder Millie Bright, who made her debut as a substitute against Belgium last month, retains her place in the squad of 23 players.
Sampson's side will face France in Doncaster on Friday, 21 October, before travelling to Guadalajara to face Spain on Tuesday. 25 October.
England have never won in Spain and lost 3-2 in their last meeting as they exited Euro 2013 at the group stage.
"Both France and Spain will be challenging matches for us but these are the type of opportunities this group looks forward to and are an important part of our preparations for next summer," said Sampson.
"We will be working hard over the camp to prepare ourselves as best we can to win both matches while also having one eye on the Euros."
The Lionesses will find out their opponents for Euro 2017 in the Netherlands when the draw is made in Rotterdam on Tuesday, 8 November.
England women squad:
Goalkeepers: Karen Bardsley (Manchester City), Siobhan Chamberlain (Liverpool),  Rebecca Spencer (Chelsea),
Defenders: Laura Bassett (Notts County), Lucy Bronze (Manchester City), Gilly Flaherty (Chelsea), Steph Houghton (Manchester City), Alex Scott (Arsenal), Demi Stokes (Manchester City), Casey Stoney (Arsenal),
Midfielders: Millie Bright (Chelsea), Isobel Christiansen (Manchester City), Jade Moore (Notts County), Jordan Nobbs (Arsenal),  Jo Potter (Notts County),  Jill Scott (Manchester City), Fara Williams (Arsenal).
Forwards: Karen Carney (Chelsea), Danielle Carter (Arsenal), Rachel Daly (Houston Dash), Gemma Davison (Chelsea), Toni Duggan (Manchester City),    Nikita Parris (Manchester City).
Manchester City striker Toni Duggan has been recalled by England women coach Mark Sampson for the games against France and Spain this month.