Feeding the famous monkeys has been punishable with fines for some time, but enforcement of the regime has been relatively lax.
Now the UK-held territory is looking to clamp down on the activity with a regimen of fixed fines, the Gibraltar Government said in a recent media release.
People who feed the monkeys within Gibraltar's Upper Rock Nature Reserve will be slapped with a fixed fine of £500 (€600) if the rules changes are introduced.
Giving the macaques food outside of the nature reserve will mean a smaller fine of £250.
Under the proposed changes, officers from Gibraltar's Department of the Environment and the Environmental Agency will be able to issue tickets to offenders, as well as police.
Gibraltar's environmental authorities hope the changes will help secure the future of The Rock's 230-strong monkey population.