Gemlik is a coastal town with a potential of tourism and historical background. Gemlik was once the site of the ancient Greek city of Kios/Cius.

Gemlik is at the middle of the by the Samanlı Mountains to the north, and the Katırlı Mountains to the south, with the Gulf of Gemlik, a southeastern inlet of the Sea of Marmara, widening towards the open sea westwards from the town. It's because of this particular topography that you will briefly and unexpectedly see the sea in Gemlik while travelling between Yalova and Bursa. This gave life to the three-liner of the famous Turkish poet Orhan Veli Kanık (1914–1950), "Towards Gemlik / You'll see the sea / Don't be surprised", which is much celebrated locally. There is a large plain spanning much of the east end of Gemlik to the coast. Karsak Stream, which originates at İznik Lake, divides this plain into two parts.

Before the Exchange of the population in 1922 between Turkey and Greece the population of the city includes around % 80 Greek inhabitants. As stated before it was an ancient Greek city and has ruins of some ancient Greek structures like Hagios Abarkios Monastery and Michael Gabriel (Archangel) Church which are both sited on Kurşunlu.

After the rebuplic of Turkey was founded a Gemlik-born citizen “Celal Bayar” served the nation as 2nd prime minister and 3rd president of Turkey respectively. After his death in 1986 a mausoleum was constructed for his burial in 1993. The mausoleum is one of the most-sighted sites on Gemlik.

Addition to these historical sites, the beaches of Kurşunlu and Kumla are the basis of the tourism at Gemlik. Originally 100.000 populated Gemlik doubles its own population during the summer seasons. Especially Kumla is one of the most favouirite locations at Marmara Sea because of its contiguity to Bursa and İstanbul.

Finally Aytepe, Libraray of Celal Bayar and Beyler Graveyard are the other well-known places at Gemlik worth for visiting.