A survey by YouGov found that 65% of respondents said they thought the SNP was against Brexit, the highest figure for any political party.
The Liberal Democrats, who were the first party to back a second EU referendum, were seen as anti-Brexit by 53% of respondents.
The poll highlights the problems facing both Labour and the Conservatives as they try to communicate a clear Brexit policy to voters ahead of local elections this week and European elections on 23 May.
Labour is seen as anti-Brexit by 42% of respondents, while 13% believe it is pro-Brexit. 20% of people said Jeremy Corbyn’s party was neither for or against Brexit, and 25% said they didn’t know.
The polling comes on the same day as a crunch meeting of the Labour national executive to decide whether its European election manifesto will include a commitment to hold a second EU referendum.
Voters are overwhelmingly clear on the stance of Ukip, which 71% of respondents said was pro-Brexit, and Nigel Farage’s Brexit Party, which was identified as the most Eurosceptic party on 79%.
YouGov collected responses from 1730 people across the UK on 24 and 25 April.