How accurate were the polls at the last Spanish general election?
Short answer
They overstated the PP and Vox. Before the election on Sunday 23 July 2023, most final polls put the two parties together at or above the 176 seats needed for a majority; they won 170, and every final poll underestimated the PSOE.
Detailed answer
At the general election on Sunday 23 July 2023, the PP won 137 seats and Vox 33, a combined 170, six short of the 176 needed for a majority in the 350-seat Congress of Deputies. The PSOE won 121 seats and Sumar 31. Pedro Sánchez was re-elected Prime Minister on Thursday 16 November 2023.
What the final polls said
We compared the last poll from each of 18 pollsters with fieldwork ending between Monday 10 July 2023 and Monday 17 July 2023, before the legal ban on publishing polls. Taking the middle of any range:
- 13 of the 18 put the PP and Vox together at 176 seats or more.
- Their combined projections ran from 170 to 183 seats, averaging about 178.
- 14 of the 18 put the PP above the 137 seats it won.
- All 18 put the PSOE below its result. The highest projection was 115 seats, against the 121 it won.
Why the polls missed
Analysis after the election pointed to small samples in each of the 52 constituencies, late-deciding voters who appear to have leaned towards the PSOE, and tactical voting in Catalonia, where the PSOE won 19 seats. Vote share estimates were closer to the result than seat projections.
What it means for 2026
Polls can all be wrong in the same direction. Our Spanish election tracker allows for this with a shared error that moves every poll together, which is why the meter does not show certainty even when all the polls agree. It summarises published polling and is not a forecast.