Arabic is now the largest minority language in Sweden, according to the newspaper Svenska Dagbladet.
It replaces Finnish, which was the number two language in Sweden for hundreds of years.
Sweden's open door immigration policy has attracted hundreds of thousands of primarily Muslim immigrants from the Middle East.
Swedish linguist Mikael Parkvall calls the shift a "historical milestone." He estimates the number of Arab speakers has doubled over the last 10 years and is now "over 200,000" out of a population of 10-million people.
One Swede tweeted about the news, "The next milestone will be when Arabic becomes the LARGEST native language. It will only take a few decades."
Sweden's immigration policy has become so unpopular among some citizens that the anti-immigration Sweden Democrats are now the third largest largest political party in the nation.
English was not included in the list of minority languages because it is so widely spoken. An estimated 86% of Swedes are proficient in English.