Thursday in Melbourne, Australia the sisters achieved another milestone, each advancing to the Australian Open final. There, they will face each other for the ninth time, and the first since 2009, for a Grand Slam title. World number two Serena will claim the Open-era record outright if she takes a 23rd Grand Slam title in Melbourne.
Serena eased past the unseeded Mirjana Lucic-Baroni of Croatia 6-2 6-1 in the second semi-final.
Venus has seven Grand Slam crowns to her name but has never managed to win the Australian Open and hasn't contested a Grand Slam final since 2009, when she lost out to Serena at Wimbledon.
The two American sisters have faced each other in eight major finals in the past, with Serena leading 6-2.
Speaking after her win, Serena said: "I am really proud of Venus - she is a total inspiration. I am really happy for her and to be in the final together is a dream for us.
"She is my toughest opponent, no-one has ever beaten me as much as Venus."
"I feel no matter what that we have both won after all we have been through. I know a Williams is going to win this tournament."
Serena beat Venus in the 2002 Australian Open final and leads the head-to-head between the two stars 16-11.
