Vietnam’s government has invited global investment banks to pitch for a mandate to sell a stake in the country’s largest beer company worth at least a $1.8 billion, according to people familiar with the situation, kicking off what could be the largest sale of a Vietnamese state-run firm.

The sale process for Saigon Beer Alcohol Beverage Corp., or Sabeco, would kick off in April, said Phan Dang Tuat, head of Vietnam’s Ministry of Industry and Trade’s Enterprise Reform Commission, confirming that the government has invited banks...