The figure was 23.5% higher than the same month last year, the Treasury and Finance Ministry announced.
The gross debt stock includes the outstanding debt of public sector institutions, the Central Bank, private companies, and households.
More than half of the debt stock, 818.4 billion Turkish liras ($119.5 billion), is denominated in foreign currency, the ministry said.
Nearly 984 billion Turkish liras ($143 billion) of the debt was domestic and 657 billion liras ($96 billion) were external, it added.
The stock of Treasury receivables stood at 18.2 billion Turkish liras (nearly $2.6 billion) as of June 30.
The U.S. dollar/Turkish lira exchange rate was 6.85 at the end of last month.