Back to School Sales Tax Holiday in Kansas City,Missouri shopping areas.
By state law, the sales tax holiday begins on the first Friday in August and continues through the following Sunday. In 2015, the three-day holiday begins at 12:01 a.m. on Friday, Aug. 7, and runs through Sunday, Aug. 9.
Certain back-to-school purchases, such as clothing, school supplies, computers, and other items as defined by the statute, are exempt from sales tax for this time period only.
http://dor.mo.gov/business/sales/taxholiday/school/