The Lizzie McGuire star tied the knot with hockey player Mike in a romantic ceremony in Santa Barbara, California on 14 August 2010.
They welcomed son Luca Cruz Comrie two years later.
Today, Hilary, 25, wrote on Twitter: "3 yrs ago today I married a wonderful man! So lucky we found each other. He also gave me the most precious boy I ever layed my eyes on!!."
Hilary and Mike met in 2007 when they were both visitors at the same Idaho resort. They became engaged in February 2010 during a romantic holiday to Hawaii.
They said their vows in front of 100 friends and family in a candle light ceremony that summer and later honeymooned in Mexico.
3 yrs ago today I married a wonderful man!So lucky we found each other.he also gave me the most precious boy I ever layed my eyes on!!— Hilary Duff (@HilaryDuff) August 14, 2013
Unfortunately for Hilary, her wedding day didn't go off entirely smoothly - she lost a tooth in the morning while munching a bagel just three hours before she needed to start getting ready.
She told the Ellen DeGeneres Show later: "I burst into tears. Then I started laughing at myself, and then I really burst into tears."
Luckily, she found an emergency dentist who treated her in time for her to walk down the aisle.
Hilary and Mike became parents to their son Luca on 20 March 2012, with Hilary tweeting at the time: "Wow, I can't believe I have a baby! Thank you for all the messages and well wishes. I love you all so much."
Hilary's made no secret of how much she's loving life as a mother but has said it might be a while before we see a baby number two.
She told InTouch magazine in May this year: "I'm not trying for baby number two anytime soon. I'm focused on Luca."