The National Assessment Program Literacy and Numeracy tests are run each May for all students across Australia in years three, five, seven and nine.

Students are assessed on reading, writing, language conventions and numeracy.

Results were published on the My Schools website this week.

St Mary's School in Donald received substantially above average results in all areas for year five, as well as year three spelling, grammar and numeracy, and above average results for year three writing and reading.

Principal Daniel Gooch said the school was pleased with the results.

"We have had good results in the past few years now," he said.

He said it was encouraging to know students were doing well.

"It is just a small part of the big picture though," he said.

"We use the NAPLAN results as another data source to track student learning.

"We also use that information to inform teachers and help them develop learning programs."

Other Wimmera schools among the best were Edenhope P-12 College, Hopetoun P-12 College and Horsham's Holy Trinity Lutheran School.

Edenhope College acting principal Robyn Hollis said the year three and year nine results were particularly pleasing.

"Results can change depending on the year levels, but it's pleasing to see we are doing well," she said.

"We have a particular focus in the early years on the importance of literacy and numeracy.

"As teachers, we are always trying to make sure we stay in touch with current practices and curriculums."

Ms Hollis said it was important to note that NAPLAN was just one indicator of student performance.

"High quality teaching and learning and high expectations for all year levels, throughout the whole year, helps our students be the best they can be," she said.

Ararat schools were among the worst, with both Ararat North Primary School and Ararat Secondary College scoring substantially below average results in all areas.