The difference between men's and women's full-time median hourly pay excluding overtime fell from a revised 9.6% in 2015, but it remains at around 20% for high earners, said the Office for National Statistics (ONS).
Minister for Women and Equalities, Justine Greening said it was "fantastic" to have the lowest gender pay gap on record, adding there was more to do to close it.
"That's why we are pushing ahead with plans to require businesses to publish their gender pay and gender bonus gap for the first time ever from April next year."
The 9.4% is th e lowest figure since current records began in 1997, when it was 17.4%, although the gap has narrowed relatively little in recent years, said the ONS.
The difference for all workers, including part-timers, fell from 19.3% last year to 18.1%, the biggest annual drop since 2010.
TUC general secretary Frances O'Grady said: "The full-time gender pay gap is closing at a snail's pace. At this rate, it will take decades for women to get paid the same as men.
"We need a labour market that works better for women. This means helping mums get back into well-paid jobs after they have kids, and encouraging dads to take on more caring responsibilities.
"The Government should also scrap tribunal fees, which stop women getting justice from bad employers who have discriminated against them."
The ONS said the introduction of the national living wage of £7.20 an hour for adults had led to pay growth in the past year being at the bottom end of the earnings scale.
ONS statistician James Scruton said there was a definite pay boost for those previously paid below the rate, adding that there was a similar pattern when the national minimum wage came into force in 1999.
The figures, for April this year, showed that weekly earnings grew by 2.2% for full-time workers and 6.6% for part-timers.
The CBI's skills director Neil Carberry said: "This data confirms a picture of low but robust wage growth across the UK economy before the EU referendum.
"It's clear that the introduction of the national living wage has supported lower earners' incomes, building on several years of higher than average increases in the old national minimum wage."
Laura Gardiner of the Resolution Foundation, said: "The introduction of the national living wage has well and truly made its mark on pay across Britain."