Robin van Persie's summer departure received plenty of criticism from Arsenal fans after the board decided to sell their most prized asset to title favourites Manchester United.
Even though the club have been boosted by the contract renewals of Theo Walcott and Jack Wilshere, the France striker believes that more money must be spent by the board in order to purchase top talent across Europe.
Giroud told Sky Sports News how Arsenal can compete for trophies: "First you need to keep your best players, that's so important. After that, maybe you need more money.
"But Manchester United every year buy one or two players. They manage to keep their best players, I think that's the main thing to do."
Before making his move to Arsenal, the former Montpellier striker was linked with German league leaders Bayern Munich, but he admitted he has been happy since joining the London side.
He added: "Munich were not ready to take a decision. I was really happy to sign for Arsenal.
"Thierry Henry, Patrick Vieira, Robert Pires, Sylvain Wiltord, Emmanuel Petit - there have been a lot of French players, so that's why I supported this team."