Phil Jackson of the Educational Institute of Scotland (EIS) said teachers and pupils should never again have to "endure the stress and pressure they have this year" following the introduction of the new National exams, which have replaced Standard Grades.
Speaking at the EIS annual general meeting in Perth, Mr Jackson added: "We truly are at a crossroads in education where the Government must choose what its priorities are."
However, the Government said it had listened to concerns and was working with the union to tackle the "unnecessary paperwork" to free teachers to concentrate on delivering education.
Meanwhile, learning minister Dr Alasdair Allan praised pupils and teachers for their hard work as the exam season drew to a close today.
He said: "To pupils, I would like to say well done on all your hard work.
"I hope you can now enjoy a relaxing summer break."