The Israeli actress, 38, revealed the news by sharing a photo of her in a hospital bed cuddling her daughter, named Ori.
Gadot has three more daughters - Alma, 12, Maya, six, and Daniella, two - with husband Jaron Varsano.
View this post on Instagram A post shared by Gal Gadot (@gal_gadot)
Alongside the photo posted to Instagram, she wrote: "My sweet girl, welcome. The pregnancy was not easy and we made it through.
"You have brought so much light into our lives, living up to your name, Ori, which means 'my light' in Hebrew. Our hearts are full of gratitude.
"Welcome to the house of girls ... daddy is pretty cool too."
Her husband re-shared the picture and added: "Bliss! Thank you my beautiful strong lioness.. Forever my beating heart."
Among those to congratulate Gadot was Emily In Paris actress Lily Collins, who wrote "Ahhhhh congratulations!!!", while US actor Vin Diesel posted a pray emoji.
US model Lily Aldridge also shared her congratulations, as did Breaking Bad star Aaron Paul, who wrote: "Congratulations!! So beautiful."
Gadot married Israeli property developer Varsano, 49, in 2008.
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