The bill allows the use of cannabidiol, an oil extract, to be administered under the care of a doctor. The measure falls far short of legalizing the use of marijuana for medical purposes.
Walker said Wednesday he signed the bill because it is "very narrowly crafted. It is not medical marijuana."
Walker says his Capitol office was full of families and children who suffer from seizures and who may be helped by using the oil.
The bill unanimously passed the Legislature earlier this year. Republicans who control the Legislature have shown no interest in legalize medical marijuana let alone recreational pot smoking like in Colorado and Washington.