"On the first day of 2024 I wanted to wish you a happy new year and share the exciting news that Jiri and I will be welcoming a baby into our family this summer!" Kvitova said on Instagram.
The 33-year-old world number 17 married her coach Jiri Vanek in July 2023.
"While I will miss my annual trip to Australia and competing in the sport I love, I'm looking forward to spending some time at home preparing for this exciting next chapter in our lives," she added.
Kvitova, the Wimbledon champion from 2011 and 2014, has won 31 WTA singles titles.