No. There is no indication that there will be a Curious George 3. Actually, I did find some web pages about the first Curious George movie and Curious George 2, but they still have not realeased a concrete announcement about a third Curious George movie.
No.
Curious George 3 Back to the Jungle, the animated direct-to-dvd film released August 17th 2015.
Curious George - 2006 Curious George Flies a Kite From Scratch 1-1 was released on: USA: 4 September 2006
Curious George - 2006 Relax The Box and the Hound 3-12 was released on: USA: 16 February 2010
Curious George - 2006 DJ George Curious George Paints the Desert 6-7 was released on: USA: 16 April 2012
Curious George - 2006 For the Birds Curious George-Asaurus 3-3 was released on: USA: 3 September 2008
No.
Curious George - 2006 Zeros to Donuts Curious George Stain Remover 1-3 was released on: USA: 6 September 2006
Curious George - 2006 Hundley Jr- Curious George Gets Winded 7-3 was released on: USA: 5 December 2012
Curious George 3 Back to the Jungle, the animated direct-to-dvd film released August 17th 2015.
Curious George - 2006 Curious George Flies a Kite From Scratch 1-1 was released on: USA: 4 September 2006
Curious George - 2006 Juicy George The Big Picture 4-3 was released on: USA: 23 November 2009
Curious George - 2006 Curious George on Time Curious George's Bunny Hunt 1-5 was released on: USA: 13 September 2006
Curious George - 2006 Gnocchi the Critic George Cleans Up 3-11 was released on: USA: 9 September 2009
Curious George - 2006 George's Super Subway Adventure Well Done George 5-3 was released on: USA: 8 September 2010
Curious George - 2006 Curious George's Rocket Ride Curious George Train Master 1-14 was released on: USA: 9 October 2006
Curious George - 2006 Curious George Discovers the Poles Curious George Finds His Way 1-10 was released on: USA: 27 September 2006