Over 31,000 people have signed a petition calling for a "kid's strike" of the SATs exams on May 3rd.
The 'Let Our Kids Be Kids' campaign wants parents to keep their children off school, saying they are "over-tested and over-worked".
A petition on the 38 Degrees website backing the plan to keep children at home next week has passed 31,000 signatures, including people claiming to be teachers.
In an open letter to Education Secretary Nicky Morgan, published on their website, the Year Two parents behind 'Let Our Kids Be Kids' said they "represent the voice of parents across the country" who "want an end to SATs now".
SATs (Standard Assessment Tests) are taken by children aged six or seven in Year Two and then again in Year Six, aged 10 or 11, before a third set in Year Nine aged 13 or 14.
Parents are being urged by the campaign to keep their children off school for "a day of educational fun instead".
A Department for Education spokesman said: "Only exceptional circumstances warrant a child being taken out of school during term time.
"We are clear that tests should not be a cause of stress for pupils - they help us ensure schools are performing well, and we know the best schools manage them successfully."
He added: "We know mastering the basics of literacy and numeracy at primary school has a huge impact on how well children do at GCSE, which is why we are determined to raise standards."