West Ham gambling sponsor fined £400,000 for marketing on kids pages
Last year, BBC Sport found the Hammers' website included a direct link to bet on a 'colouring in' page which featured a picture of a teddy bear.
West Ham were one of seven clubs with links to betting sites from children's pages, which break regulators' rules.
But the commission could not confirm if action would be taken against them.
The clubs included Premier League sides Arsenal, Tottenham, West Ham and Aston Villa, plus QPR, Millwall and Reading from the Championship.
Betway was fined a total of £408,915 for also having the firm's link on West Ham's 'Young Hammers at Home' webpage.
Both advertisements breached Commission rules stating gambling advertising must be socially responsible.
The club website has since been updated.
Leanne Oxley, Gambling Commission director of enforcement, said: "Protecting children from gambling harm is at the heart of what we do.
"Although there is no suggestion that the operator was deliberately targeting children, or that children had been allowed to gamble, we take the breach of any rules aimed at protecting children extremely seriously.
"We note the remedial actions since taken by licensee but advise all operators to learn from this case and ensure that they take responsibility and have the correct processes in place so that websites directed at children do not include advertisements for gambling."
James Grimes from campaign group The Big Step said: "This is one of the worst examples of gambling advertising in football and so action is welcome but fines are not enough and not a deterrent - this won't be the last time a gambling company advertises their products in front of children.
"By continuing to promote gambling across football, clubs are risking the health and lives of their own young fans - the stakes really are too high. This is yet more evidence that the government must end all gambling sponsorship in football and get on with it."