Zuckerberg said on Facebook and Instagram over the weekend that "you'll hear from me a little less" during this time.
Facebook offers four months of paid parental leave for both mothers and fathers - generous for corporate America, although some tech companies offer more.
The paid leave doesn't need to be taken at once. Zuckerberg took a month off after his second daughter, August, was born in August. Max was born in 2015.
When he took his first leave, Zuckerberg wrote that he's "pretty sure the office will still be standing when I get back."