Erdogan believes the US was behind the 2016 coup attempt against him
The pledges of support came after opposition leader Juan Guaido declared himself interim president of Venezuela in an address to tens of thousands of people on the streets of the capital, Caracas.
"We are with you," Turkey's President Recep Tayyip Erdogan told Maduro in a telephone call, according to his spokesman Ibrahim Kalin. "My brother Maduro. Stay strong, we are by your side."
Erdogan said the democratic process must be respected.
"As a country that believes in democracy ... wherever in the world there is a coup attempt, we stand against them all without distinction. Everyone has to respect the result of the ballot boxes."
Turkey's Foreign Minister Mevlut Cavusoglu later told news channel A Haber it was "very strange" that Guaido declared himself president despite the country already having an elected leader in Maduro.
"And some countries recognised him. This situation may lead to a chaos," Cavusoglu said.
He added Turkey was trying to support Venezuela's economy as it experiences serious challenges.
Since last year, Turkey has been refining and certifying Venezuelan gold after Maduro switched operations from Switzerland over concerns that further sanctions against his country could see it impounded.
Venezuela recently turned to gold in a bid to shore up its depleted foreign currency reserves as the economy implodes and international sanctions restrict the government's ability to raise foreign currency.
Source: Al Jazeera