The comment appeared to be a swipe at Conservative Education Secretary Michael Gove, who said in an interview that the Prime Minister's inner circle contained a "ridiculous" number of people who had gone to Eton.
As well as Cameron, those who attended the famous public school include his Chief of Staff, Ed Llewellyn, and the Minister for Government Policy, Oliver Letwin, among others.
In an interview published yesterday, Gove said: "It doesn't make me feel personally uncomfortable, because I like each of the individuals concerned.
"But it's ridiculous. I don't know where you can find a similar situation in any other developed economy."
Speaking to the media at the Scottish Conservative conference in Edinburgh, Maude, who attended the elite Abingdon School in Oxford, was asked if there were too many Old Etonians around the Prime Minister.
He said: "I'm much less interested in what school people went to than I am in what they do and how they do their job. I just think we can sometimes get a bit too fixated. "
Gove's remark was also seen as a coded dig at London mayor Boris Johnson, another Old Etonian, who hopes to become Prime Minister.
Gove is understood to be supporting Chancellor George Osborne for the Tory leadership if Cameron quits after a 2015 election defeat.