There was a 4% rise in the number of female professors at UK universities last year, figures show.
But they are still heavily outnumbered by men and make up just under 20% of those holding the senior post.
Figures from the Higher Education Statistics Agency (Hesa) show there were just under 3,500 female professors in 2010, out of a total of just under 17,500.
They also show a slight fall (1.5%) in the total number of university staff.
This stands at nearly 382,000, with just under half of those being academics.
There was a slight fall (0.4%) in numbers of academic staff, bringing the number to a little over 181,000.
The general secretary of the University and College Union, Sally Hunt, welcomed the increase in female professors but said there was "more to be done".
"I am pleased that there has been a rise in the number of female professors in the sector. However, universities still have more to do to ensure that staff are promoted on merit irrespective of their background or gender," she said.
"Students want to be taught by the best and brightest, and staff want to work in universities where gender is not an issue when it comes to career advancement."
The academics' union warned that the fall in staff numbers was a sign of things to come, because of the 40% cut in teaching grants for universities in England.
The government's changes to the sector in England are aimed at replacing such grants with higher tuition fees backed by student loans, so that money more directly follows students.
Ms Hunt said: "With student numbers going up, this fall in teaching staff is very concerning, especially as we prepare for the new funding regime. The inevitable result will be larger tutorial and lecture sizes, which will be bad for the student experience."
Fees at England's universities are set to rise up to a maximum of £9,000 a year from the autumn.
They are also rising in other parts of the UK, although students from Wales will be subsidised wherever they study in the UK.
Students in Scotland will continue to pay no fees at Scotland's universities, and those from Northern Ireland who study there will pay about £3,500.