The first official name of the village was given as Almali or Elmaalani in 1899, as mentioned in the archives of the prime minister.

While the name Almali was used, the name was changed to Reşadiye in 1910 after Sultan Mehmed V Reshad visited the village, was pleased by it, and had a memorial fountain built there.

In 1934, it was named Güneyköy because of its location on the southernmost shore of Istanbul's borders.

In 1919, it was invaded by the Greek Army during the Turkish War of Independence, and its inhabitants migrated to the Geyve and Adapazarı regions for three years.

Sheikh Şerafeddin Dağıstanî [tr] and Abu Muhammad al-Madani of the Naqshbandi-Haqqani Golden Chain are buried up in the cemetery of the village.