Former Bachelorette Angie Kent has always supported the sisterhood and shared two photos of herself sitting atop a car in a bright pink frock to mark the special day.
"Dearest women in my life, those of you who are no longer around, and the women I am still to meet...just a day can never be worth what you all are!" she began in her caption.
"To all my past sisters in which I hold your pain, sadness, guilt, shame.... I am healing these wounds for you, one uncomfortable conversation at a time, every opportunity, every chance I get to speak my truth and call out what no longer serves us!
"It’s been quite the slog, but it is worth it, and each day changes are being made (or at least finally being noticed and called out) Can’t stop, won’t stop. So here’s me in a pink dress, on a pink Jeep with my little kangaroo trotters in all their glory, being extra as f*ck letting you know, you ladies you are my superhero’s!"
The former Bachelor runner-up is a proud feminist (she even has a tattoo to prove it) and had the best advice to anyone who wants to explain to the men in their lives why IWD is needed in 2021.
"First of all kindly remind them there's International Men's Day on November 19th, give that a quick Google," she opened.
"But also remind them that women have been oppressed, silenced and marginalised throughout the entirety of our patriarchal society and today is a day to celebrate the strength, the changes and the changes to come within that patriarchal society through female empowerment."
MasterChef judge Melissa Leong is a trailblazer in many ways and remarked in her post - a print that reads "The Power Of Women" - that she is getting stronger and more sure of herself with every year.
"With every year, I become more of myself. Able to claim who I am and stand up for it, unapologetically, in my flaws as well as my triumphs," she penned on Instagram.
"As a woman of colour living in this time, I feel the palpable capability of how much change we can make…but also how far we are from the world being right or fair.
We are resilient, multi-faceted, beautifully complex and f***ing fierce. We work it for our sisters, friends, daughters and mothers, as well as for ourselves and those we don’t even know.
She finished by saying: "To you, I hope you find your inner strength to claim your space in this world, and use it to fight for kindness, support and progress."
It's an oldie but a goodie - Bindi Irwin, who is expecting her own daughter in the coming weeks - shared a poignant quote to mark International Women's Day.
“'Here’s to strong women. May we know them. May we be them. May we raise them,'” she captioned a photo of herself and mum Terri Irwin cradling her baby bump.
Last year was a turning point for Michelle Bridges but the fitness queen is embracing the #ChooseToChallenge theme with her raised hand photo to show she's committed to calling out inequality.
"She is strong. She is passionate. She is emotional. She is brave. She is WOMAN," the former Biggest Loser trainer captioned her snap.
"This International Women’s Day I #choosetochallenge with my 12WBT team. We stand together with those fighting for equality and the chance to speak their truth."
Though she shared a selection of photos celebrating the "many beautiful women" in her life, the 2020 Bachelorette gave a special shout out to her big sister and fellow Bachelorette Becky Miles.
"HAPPY BIRTHDAY TO THE BEST SISTER IN THE WORLD," she captioned a series of photos of herself and her sister.
"The fact that today is also International Women’s Day is quite fitting because you are one of the most influential women in my life and I look up to you immensely. You have always been so kind, considerate, loving and caring to those around you. You are always exuding good vibes and just want everybody to be happy."
Elly added: "I know for a fact that I wouldn’t be the person I am today without you sis. I am extremely proud of you and proud to be your sister. I have so many cherished memories with you and I look forward to creating more! Happy Birthday you incredible woman. Have the best day ever!!"
For her International Women's Day post, Delta threw it back to her time as a coach on The Voice when she and fellow coach Kelly Rowland sang a duet rendition of Chaka Khan's I’m Every Woman.
“'Anything you want done baby, we do it naturally'”, Delta wrote in her caption.
"Happy #internationalwomensday to the doers, the dreamers, the achievers. The boss ladies and queens, mentors and friends.... those who fight and love with their whole hearts! Your strength knows no bounds 💪🏼🌸⚡️🔥 with my @kellyrowland xx 👯♀️ #iwd2021
From his wife Jasmine Yarbrough to his daughters Ava and Harper to his mum Jenny to the many more, Today Show host Karl Stefanovic shared his gratitude to the women in his life via an Instagram post featuring several photos.
"They make my life. #internationalwomensday," he simply wrote in his caption.
Like Michelle Bridges, former Bachelor Matt Agnew chose to pose with his hand up to symbolise how he's choosing to challenge gender inequality.
"I also wanted to share some truly inspirational women, not just because of their extraordinary contributions to science, but because of the the impact they’ve made in the world," the astrophysicist wrote.
"Marie Curie. Discovered the elements radium and polonium, which revolutionised medical science by finding a means by which to treat cancer. Winner of the Nobel Prize in Physics in 1903 and Chemistry in 1911, and the first woman to win a Nobel Prize.
"Katherine Johnson. Mathematician and computer. Integral in calculating trajectories for a myriad of spaceflight missions including Mercury, the first human spaceflight missions, and Apollo, the missions to put a human on the Moon.
"Jane Goodall. Primatologist and anthropologist. The world’s foremost expert on chimpanzees, and an advocate for animal welfare and conservation causes.
"Christina Koch & Jessica Meir. The two astronauts that conducted the first woman only spacewalk in 2019, replacing a battery charge/discharge unit on the International Space Station.
Matt finished by remarking: "Here is to the women championing progress and inclusivity in our world."
New Zealand Prime Minister Jacinda Ardern has been a role model for girls and women in her home country and around the world and shared an image of a brooch on International Women's Day that holds special significance.
"I was given this brooch a while ago to mark the 125th anniversary of women’s suffrage in New Zealand. On the back it has the number 99. That’s because I’m the 99th woman to enter parliament since we‘ve been able to run for office," she wrote in her caption.
"I sometimes find that hard to fathom. Only 99?! But at the same time, that’s 98 women who worked so hard laying the path to make it easier for woman and for me to become a young activist, then an MP, a mother and a Prime Minister. On this day I salute the 98 women who have gone before me, and the 75 since!"