The property website has announced it will not seek to continue backing the club after this season.
Zoopla was unhappy at the continuing presence of Anelka in the team while his actions were investigated by the Football Association.
It was also claimed that Zoopla had requested Anelka play in an unbranded shirt during the Baggies' Barclays Premier League game against Everton on Monday night.
There has been no confirmation of that but the company, which is co-owned by Jewish businessman Alex Chesterton, is to end its support after its obligations for this season end.
A statement from the company read: "Zoopla has been reviewing its position over the past few weeks in light of the actions of striker, Nicolas Anelka, during the match against West Ham over the Christmas period and has decided to focus its attention on other marketing activities after this season."
Lawrence Hall, head of communications for Zoopla, said: "Through our sponsorship of West Bromwich Albion we are pleased to have supported the local community and charities.
"In recent weeks, however, we have decided to re-evaluate this sponsorship and as a result we will focus our attention on other marketing activities from the end of the season."
The FA launched an investigation after Anelka sparked controversy by performing the quenelle gesture as he celebrated scoring at West Ham on December 28.
The gesture, which has caused outrage in Anelka's native France, has been declared by some to be anti-Semitic or racist.
Anelka denied he was being anti-Semitic or racist and said he did it in support of his friend Dieudonne M'Bala M'Bala, a controversial anti-establishment comedian.
Since beginning its investigation, the FA has made no comment other than to state an independent expert has been used during its probe.
The governing body has faced criticism for the length of time its investigation has taken but it had pledged to be thorough.
It is thought there could be an outcome this week, with the possibility Anelka, 34, could face a ban.