The 31-year-old, who tested positive for methylhexaneamine at the Glasgow Games in July, plans to appeal against her ban and has until March 26 to do so, local media reported.
The Botswana Athletics Association (BAA) delivered its verdict last month following six months of investigations after Montsho's’s A and B samples tested positive for the drug.
The case was first investigated by the Commonwealth Games Federation (CGF), which found the athlete guilty of violating its anti-doping code.
It was then handed to the International Association of Athletics Federations (IAAF) and finally referred back to the BAA to determine a punishment.
Montsho was the poster girl for Botswana athletics having won gold at the 2010 Commonwealth Games in New Dehli, the first athlete from her country to do so, and being crowned 2011 world champion in Daegu, South Korea.
She also won the silver medal at the 2013 world championships in Moscow, losing out in a thrilling photo finish to Briton Christine Ohuruogu by four thousandths of a second.
If it is upheld, the suspension would probably end Montsho's career at the highest level.
(Reporting by Nick Said, editing by Ed Osmond)
