The Marine Conservation Society (MCS) event, which will take place from 16 to 19 September, attracted 1,421 Scottish volunteers last year.
It involves groups working on 100m stretches of coastline.
Information from the clean-up is used by MCS to work with governments and industry to stop beach littering.
Lauren Eyles, MCS Beachwatch manager, said: "We'd love to see people heading to the Scottish coastline and helping clean up at the events that have been organised.
"It helps us identify different litter sources and raise awareness of particular problems.
"We're currently running a campaign for clearer wet wipe labelling after our volunteers found, on average, 50 wet wipes per kilometre of beach they cleaned.
"So far, almost 6,000 people have supported our petition to get retailers to make their packaging clearer."
The Scottish beaches where clean-ups are planned are Invergordon West, Kerrycroy, Kames Bay on Bute, Tain, Ettrick Bay on Bute' Greyhope Beach, Nigg, Aberdeen North, East Haven, Bo'ness - Grangepans on the John Muir Way, Cramond, The Corran, Broughty Ferry East End, Blackness, Tentsmuir Point National Nature Reserve, Brora North, Arrochar Shore, Dornoch Sands, Port Alltan na Bradhan, Limekilns, Kinghorn Harbour, Forvie National Nature Reserve, Johnshaven, Ullapool East Shore Beach, Spey Bay, Arbroath West, Lunan Bay North, Tarbat.
Volunteers are being urged to take part in the Great British Beach Clean after just 79 people signed up to work on 28 Scottish beaches.