The 36-year-old decluttering expert announced news of her pregnancy in January.
At the time, Kondo shared a photo of her growing bump on Instagram and captioned the image: "I have some news! Another bundle of joy on the way. (heart emoji)"
Her TV producer husband - who she married in 2012 - shared the announcement on his Instagram Story and added: "Thank you so much!!"
Kondo previously admitted she had let her "perfectionist" tendencies slide since having children.
She said: "I used to be a perfectionist, but it became difficult to maintain that standard after having my children. So much was out of my control.
"I hope my openness on the subject will help others to ease up on impossible standards. I gave up on perfectionism a while ago!"
And the "The Life Changing Magic of Tidying Up" writer admitted her kids won't clean up on their own.
However, she added: "But they will when I ask them to!
"We make it a daily practice and tidy together at the end of the day."
Kondo doesn't worry if her children "have tantrums" and does her best to find out why they are acting out.
She said: "It's quite natural for kids to have tantrums — when they do, they do!
"I take the time to listen. Once they've calmed down, I ask them what's bothering them and then, to let them know I understand, I say, 'So that made you sad,' or 'That's what you didn't like.' I try to honour their feelings."
