Middling, if you're honest about it. Across this part of South Gloucestershire, about half of the graded schools come out as good or better. Five hold the top mark of outstanding. Five sit at requires improvement, and one is rated inadequate. So the good schools are genuinely good, but the average is exactly that, an average, and the gap between the best and the worst is wide enough to matter.
Of the roughly one hundred schools graded across the wider area, only around fifty carry a good or outstanding rating. That is the number to keep in your head when an estate agent describes the schooling as a selling point. Half the schools clearing the bar means half aren't, and which side of the line your nearest one lands on is the whole game. The five outstanding schools are a real draw. The one rated inadequate is a real problem for the families closest to it. Both facts are true at once, and the postcode you pick decides which one is yours.
The catchment point is the one people learn too late. A school sitting a mile from your front door is not a school your child is guaranteed to attend, because admissions run on published criteria and distance rather than on which house you liked the look of. Being near a good school and being inside its intake are two different things, and the second one is the one that counts. Check the actual admissions arrangements for the specific year you're applying, not the reputation, and not the assumption that proximity settles it.
For primary-age children the nearer options include Olveston Church of England Primary School, Gillingstool Primary School, Manorbrook Primary School and St Mary's Church of England Primary School in Thornbury, along with the Crossways infant and junior schools and St Helen's Church of England Primary School. That is a decent spread of choices on paper, though a spread of choices is not the same as a spread of places, and the popular ones fill on distance. For secondary, the names in the frame are The Castle School and Marlwood School. There are also specialist and alternative provisions in the wider area, including New Siblands School and Two Bridges Academy, which serve particular needs rather than the general intake.
A word of caution on names you might half-remember. Schools close, merge and rebrand, and a school that existed when you last looked may not be an option now. The safe move is to work from the current admissions lists rather than an old memory or a neighbour's out-of-date recommendation, and to confirm any school is still open and still taking pupils before you build a house move around it.
So what are the schools like in Alveston? Fine on average and excellent in a few specific spots, with a genuine weak tail underneath. Pick your street to land inside a good catchment and you'll do well. Pick it on the view and leave the schooling to chance, and average is the most likely outcome.