"Without the voices of more than half the world's population, how can we understand the whole story?" Irina Bokova, Director-General of Unesco, said in her message for the day that was observed Thursday.
In 2011, the Unesco General Conference proclaimed Feb 13 as World Radio Day, the day United Nations Radio was established in 1946. Radio is the most prevalent mass medium, with the ability to reach up to 95 percent of the world's population.
World Radio Day aims to celebrate radio as a medium, to improve international cooperation between broadcasters, and to encourage major networks and community radio alike to promote access to information, freedom of expression and gender equality over the airwaves.
This year, the day has a dual theme: To promote the voice of women over the air waves, and to enhance the role of women within broadcast organizations.
Radio, said Bokova, was vital for promoting gender equality and the empowerment of women.
"From pioneering executives in the early 20th century to those today reporting from conflict zones, women have played a key role in the growth of radio," she said.
"As citizen journalists, reporters, producers, technicians and key decision-makers, women are working at every level of the broadcasting industry to ensure the free exchange of opinion, information and ideas over the airwaves."
"But there is still much work to do," she stressed, noting that less than one quarter of radio stories are about women, and women represent less than one-third of all top-level management and governance positions in media.
UN Secretary-General Ban Ki-moon, in his message, underlined the need for radio broadcasters everywhere to promote the voice of women and to enhance the role of women within broadcast organisations.
"The airwaves have frequently lagged behind when it comes to gender equality. Not nearly enough women's voices are heard -- either in front or behind the microphone," he stated.
"Not nearly enough stories about women and girls are being told. And women make up only a quarter of the members of the boards of the world's media enterprises," he added.