Pollsters found nearly a third of Londoners avoided some local parks because of safety fears, with the same amount fearing mooching teenagers most of all.
Over a quarter of locals were afraid of being mugged or attacked and a quarter steered clear of their park because of poor lighting at night.
The survey marked the launch of London mayor Boris Johnson’s Safer Parks Award to recognise measures by boroughs and friends’ groups to cut crime and bad behavior.
Johnson launched the award in Danson Park, Bexley, where local residents worked with police to clamp down on gangs of kids swilling booze.
Police stepped up night patrols, increased their use of stop-and-search powers and penalised a nearby off license for selling alcohol to under-age youths.
Johnson said: "We live in one of the greenest capitals in the world, with over 3,000 parks and we all have the right to use them without fear of crime.
"Everyone from early-morning joggers to kids riding their bikes after school should be able to use them with confidence. My award will recognise the hard work that goes on to keep our parks free of crime.
"From cutting down hedges to increase visibility, to installing CCTV and strong lighting, little things can make a big impact on safety and deter criminality. It’s high time we praised the people who made this happen."
Award winners can display a plaque in the park and use a certificate and logo on websites and letterheads for a year. Visit www.london.gov.uk/saferparks