Faulkner struck two key blows to halt the West Indies' bid to reel in the home side's 7-329 at Manuka Oval on Wednesday.
The tourists had edged into favouritism before Faulkner bowled Gayle and then did the same three balls later to Darren Bravo.
The International Cricket Council said Faulkner was fined 10 per cent of his match fee for "using language or a gesture that is obscene, offensive or insulting during an International Match".
"The incident related to the bowler's actions after he dismissed West Indies batsman Chris Gayle in the 38th over," a statement said early Thursday.
"After the match, Faulkner pleaded guilty to the charge and accepted the sanction proposed by the Match Referee, Ranjan Madugalle.
"As such, there was no need for a formal hearing."