"These figures show that employment continued to grow over the summer and vacancies remain at high levels, suggesting continuing confidence in the economy," the statement said.
ONS statistician Nick Palmer added that although there was a "small rise" in unemployment, it was accompanied by more people actively seeking work.
The figures also showed the total number of people in jobs remained at a record high of 31.8 million.
In the three months to August, 73.4% of women were either in work or seeking jobs, the highest rate since records began in 1971, the ONS said.
Employment Minister Damian Hinds welcomed the data, but said: "There's more to do, particularly when it comes to supporting young people into employment."