McLean v. Arkansas Board of Education, 529 F. Supp. 1255 (E.D. Ark. 1982), was a 1981 legal case in the US state of Arkansas. A lawsuit was filed in the United States District Court for the Eastern District of Arkansas by various parents, religious groups and organizations, biologists, and others who argued that the Arkansas state law known as the Balanced Treatment for Creation-Science and Evolution-Science Act (Act 590), which mandated the teaching of "creation science" in Arkansas public schools, was unconstitutional because it violated the Establishment Clause of the First Amendment to the United States Constitution.