The notes with a face value totalling £53,000 were discovered following an intelligence-led operation.
Two men, aged 35 and 39, and a 43-year-old woman were to appear in court today in connection with the raids.
They are all currently detained in custody.
On Monday and Tuesday detectives from Police Scotland Greater Glasgow CID searched three addresses - two in Glasgow and one in Ayrshire.
They recovered the suspected fake £20 Royal Bank of Scotland notes at addresses in Queens Crescent, St George's Cross and Mavisbank Gardens, in Glasgow, and Ardfin Road, Prestwick.
Today, police urged people to check notes they receive and to contact their local police office if they think any are counterfeit.
A spokeswoman said: "Counterfeit bank notes can be readily distinguished from genuine bank notes by carefully checking them.
"Police Scotland would encourage people to check notes they receive and if they think they are counterfeit, or have information about people printing, selling or passing them, they should contact their local police office via the non emergency number 101 or CRIMESTOPPERS on 0800 555111, where information can be given in confidence."