Nigel Farage has called on Sadiq Khan to focus on crime in the capital instead of preventing "nasty words".
The Labour Mayor of London has launched a video campaign calling on men "to have a word" with friends who harass women.
His campaign has been backed by sporting institutions such as Arsenal, Chelsea, West Ham and Saracens.
But Mr Farage highlighted legislation was already in place for all of these things, and questioned whether Mr Khan had an ulterior motive.
Nigel Farage called on Sadiq Khan to do more to tackle crime
GB News
He said on GB News: "I sense what you're really doing is talking about language.
"Language that you deem to be sexist, homophobic, racist, or any of those things.
"I actually think, as Mayor of London, there are two priorities that matter more than words that people utter.
"One, the number of people whose houses are burgled who don't now even get a visit from the police.
"The second is rising knife crime, record levels every single year of young teenagers being stabbed and quite a lot of them dying on the streets of London."
The capital recorded its worst ever number of deaths from teenage homicides.
Many of these victims were killed as a result of the soaring knife crime rate in London.
And statistics showed for three-quarters of burglaries in the capital there were no suspects.
Mr Farage added: "I think the priority of the police, the priority for crime, should be actual harm against the person, instead of nasty words."