The 20-year-old midfielder, the son of former Hammers star John Moncur, has yet to make an appearance for Sam Allardyce's side this season but enjoyed a successful spell on loan with AFC Wimbledon last term.
Derry told the Nottingham Post: "George is somebody I played against when I was at QPR against the West Ham under-21s and he made a big impact on me that day.
"I was in direct combat with him and he's one I wanted to have a look at. He's a fiery young lad and he's had a good upbringing at West Ham.
"(West Ham coach) Ian Hendon, who everyone knows here at Notts from his playing days, speaks very highly of him and so does Sam and that's good enough for me."