Scotland’s animal welfare charity commissioned a survey of the public to assess how many people mixed up the two.
A quarter of respondents said they thought the SSPCA was part of the RSPCA.
But they are, in fact, two entirely separate organisations with the RSPCA operating in England and Wales only.
The poll of 1144 Scots, which was carried out by ScotPulse, also showed that 16 per cent thought the RSPCA rescued animals in Scotland.
And 23 per cent of people would call the RSPCA if they found an animal in distress.
The SSPCA is now aiming to raise awareness of its work as it appeals for public donations in the face of the coronavirus pandemic.
Having turned 180 years old last December, the charity remains at the forefront of animal welfare in Scotland.
Kirsteen Campbell, chief executive of the SSPCA, said: “Many of our frontline staff, whether out on the road rescuing animals or caring for them in centres, say members of the public confuse the SSPCA with the RSPCA every day.
“We get around 200,000 calls to our animal helpline every year and this survey suggests as many as 50,000 of those people call and think we are a part of the RSPCA.
“We have a wonderful relationship with the RSPCA and work hand-in-hand with them to take on the most critical animal welfare issues of our time, such as puppy farming.
“But we think it is important people understand that, while our counterparts do fantastic work in England and Wales, we are the only national animal welfare charity in Scotland.
“We investigate animal cruelty, rescue domestic and wild animals, tackle organised crime and deliver a free education programme.”
Entirely funded by public donations, the SSPCA is continuing to respond to emergency reports of animals in need throughout the coronavirus pandemic.
Kirsteen added: “Lockdown has forced us to completely change the way we do our essential work.
“But, in the past few weeks, we’ve responded to 2000 reports of animals in need and we still have hundreds of animals in our care across our rescue and rehoming centres.
“We will continue to fulfil our duty to animals for however long this lasts. As long as animals need us, we’ll be there.”
To support the SSPCA, visit www.scottishspca.org.