Real Madrid’s Cristiano Ronaldo, Manchester City’s Bernardo Silva and AC Milan’s Andre Silva will be expected to be in the reigning European Champions’ squad for the trip to Glasgow.
The match will take place three days after Scotland’s fixture away to Israel in the UEFA Nations League, with the kick-off time still to be confirmed.
Scotland boss Alex McLeish told the SFA’s website: “Portugal will provide a stern test for our players, which is exactly what we are looking for in our opposition in challenge matches.
“The recent challenge matches against Costa Rica and Hungary were invaluable to myself and my coaching team, allowing us to get to know the players and experiment with different systems and this match will provide further opportunity for the team to develop.
“Our Nations League campaign will be in full swing when we play Portugal and it can only be a huge incentive to the players to have the opportunity to test themselves against some of the best in the world.”
The confirmation of Portugal’s visit completes Scotland’s fixtures for this year.
Scotland were drawn in a three-team group in UEFA Nations League Group C, resulting in two free international fixture dates that have now been filled by Belgium and Portugal.
Scotland last played the Portuguese in a friendly match in Braga in 2002, with the visitors winning 2-0 with a Pauleta double.