Australian soccer is standing with the 'Yes campaign', supporting marriage equality in the Australian marriage law postal survey.
Football Federation Australia chief executive David Gallop confirmed the sport's long-running support for same-sex couples to marry.
In doing so, the country's biggest participation sport joins rugby league and cricket's governing bodies.
"FFA is a founding member of Pride in Sport and supports its charter including marriage equality," an FFA spokesperson said.
"Everyone is welcome to be a part of the football community, regardless of their age, gender, sexual preference, ability or beliefs.
""David Gallop, CEO of FFA, was one of the first CEOs in the country to publicly support same-sex marriage over two years ago."
Australia's football governing organisations - AFL, NRL and FFA - have history supporting the cause, supporting a float at the 2015 Mardi Gras.
Players showed their intolerance for homophobia during the last A-League and W-League season, supporting the 'rainbow laces' campaign.
Sydney FC players also carried a rainbow flag to the pitch during a match timed alongside Mardi Gras in March as part of their inclusivity campaign.
Matildas and Canberra United striker Michelle Heyman was named sports personality of the year at the inaugural Australian LGBTI awards in March.
Her national team coach, Alen Stajcic, said he saw the round-ball code as a welcoming sport - irrespective of background or belief.
"Football has been the leader in Australia in giving people equality in all aspects of life," he told AAP.
"Whether it's sexuality or race or any different groups that we have in the country.
"Football has always been a leader in that space. I see it being a leader in this space in the future as well."
The postal survey, which asks Australians whether they support or oppose same-sex couples marrying, begins today. Responses will be collated in November.