Good, as long as your child doesn't mind a commute from age eleven. Most schools across the county are rated good or better. The town has a primary of its own. Secondary means a bus or a lift, every weekday, for years. The grades are strong. The distance is the part nobody puts in the brochure.
Ofsted has graded 122 state schools and settings across West Sussex, and 103 of them are rated good or better. That's more than four in five. Eleven are outstanding and 92 are good. Seventeen require improvement and two are inadequate. Those figures cover the whole county council area, not Petworth alone, so they tell you about the system your child enters rather than the building at the end of the road. A further 125 settings have no published grade yet. They're not yet graded, which is different from poor, and they aren't counted in any of the figures above.
Primary is the easy part. Petworth Cof E Primary School serves the town itself, and the Department for Transport's 2019 modelling puts the nearest primary about 19 minutes' walk away on average, or about 9 minutes by car. The villages covered by this page have their own schools. Northchapel Community Primary School serves the northern end towards the Surrey border. Graffham Church of England Infant School takes the youngest children on the Downs side, and Duncton CofE Junior School sits in the same belt of villages to the south. Parents in the villages tend to learn the rules on infant-to-junior transfer faster than anyone learns the bus timetable.
Secondary is where the geography takes over. The same modelling puts the nearest secondary about 17 minutes away by car, about 30 minutes by public transport and nearly two hours on foot. Nobody walks it. A child starting secondary here joins the daily car or bus run for the next five years. That's worth pricing into a move alongside the mortgage, because it costs parents' time for the next seven years.
A named school near a house is not a guaranteed place at that school. Admissions follow the council's published criteria, which usually weigh distance and other factors, and the boundary lines move with each year's applications rather than with the estate agent's description. Check the admissions rules for the exact address, and check which primaries feed which secondaries, before you agree a price. A school name on a listing is sales copy, and the council's admissions rules take no notice of it.
One more caution on names: a small school near Petworth has closed recently. Any listing or directory that still shows it as an option is out of date.
For schools, Petworth sits in one of the stronger county systems, and families who are happy to drive or bus to secondary will find the quality they came for.