While Williams has previously held the world number 1 rank, she is now 183rd - a result of playing just three professional events in the past year due to her recent pregnancy.
The 36-year-old American, who has returned to competitive tennis following the birth of her daughter last September, is now ranked 183rd.
While WTA rules allow women who miss time because of a pregnancy to enter events based on their pre-absence ranking, there is no guarantee of a seeding, a policy which has been the subject of much debate in recent months because of Williams' status.
The aim of seeds is to produced a balanced draw, so in theory the top two players would come from either side of the draw and only meet in the final.
The Wimbledon seeding committee made no other changes from the WTA rankings in picking the top 32.
Williams played her first Grand Slam for over a year at the French Open last month, reaching the fourth round before a shoulder injury forced her to quit ahead of her clash with old rival Maria Sharapova.
It has now been confirmed that the seven-time Wimbledon champion, 36, will be seeded #25.
Unless a seed withdraws before the start Cibulkova could now potentially face Halep, or Williams, in the first round.
The draw for Wimbledon is Friday; play begins Monday.
"Why should I not be seeded if I have the right to be?"
Some had argued against Williams being seeded with world number 32 Dominika Cibulkova telling the BBC it would be "unfair" as she would be the player to lose out as there are 32 seeds.
No unseeded woman has won the Wimbledon singles championship. Competitor Caroline Wozniacki and U.S. Tennis Association President Caroline Katrina Adams were also among those who voiced support for Williams.
Business Insider contacted the All England Club to find out their justification for the seeding, but is yet to receive a response.