Garanti BBVA was established in 1946 by 103 cofounders as a joint-stock company in Ankara. The founders of the Bank consisted of traders who wanted to invest their post-World War II accumulated fortunes in profitable lines of businesses. The founding capital of the Bank was TL2.5 million which was divided into 25,000 shares worth TL100 each. Garanti opened its first branch on Anafartalar Street in Ankara on June 21, 1946; the second branch was opened in Istanbul on Bankalar Street. Branch network reached 22 in 7 years. In 1950, the headquarters were moved to the building on Yeni Postane Street in Sirkeci, Istanbul.

Towards the end of 1970s when conglomerate-owned banking gained momentum, most of the share certificates of Garanti were acquired by Koc Group and Sabancı Group. In the early 1980s, first Koc Group then Sabancı Group sold their shares in Garanti to Doğuş Group.

By 1983, Garanti was completely owned by Doğuş Group. After joining Doğuş Group, the Bank held its initial public offering (IPO) in 1990 and went public. In 1993, it became the first Turkish corporation to issue shares in international markets. Improving its services continuously, it was the first bank to start working during lunch time by introducing 'Open Bank During Lunch Break' concept ('Öğlen Açık Banka') in 1995.

In 1996, Garanti BBVA acquired Osmanlı Bank. In the 90s, operational efficiency was vital for competitive advantage; therefore, the Bank focused on investments in technology prioritizing central operation infrastructures and low-cost distribution channels particularly the internet.