The team and their coach Walid Regragui waved from an open-topped bus as they were driven from the airport and around central Rabat, accompanied by dozens of police cars and motorbikes with flashing lights and wailing sirens.
The crowd cheered and some waved flares as fireworks crackled in the sky over the seaside capital.
"I'm so proud of our team. Who knows - maybe next time they could win the cup," said Adam Najah, a 27-year-old waiter from the city of Meknes.
He said he had travelled over 150 kilometres (90 miles) to "experience this historic day" and "celebrate the beautiful story of Morocco at the World Cup".
Many supporters, clad in the team's kits and waving red flags, had waited hours to see their heroes.
The team was to be hosted by King Mohammed VI later on Tuesday evening.
