Michael Cashman with join authors, journalists and human rights defenders on a march against homophobia and transphobia in Ankara on Saturday.
Mr Cashman is one of only two out gay MEPs in the 785-member European Parliament.
Gay groups in Turkey have faced court action in recent years as the country, which is a candidate for European Union membership, grapples with LGBT rights.
The march will start at the Human Rights Monument in the Turkish capital and end at the National Assembly.
Protesters will demand constitutional equality. It is the first International Day Against Homophobia march in Ankara.
“IDAHO is the day for standing and acting against all physical, moral and symbolic types of violence targeting sexual identities and sexual orientations,” organisers Kaos GL and the Pink Life LGBTT Association said.
“This day aims to be in coordination with all initiatives struggling for the equality of humankind through inspration and supporting them.
“Only the rainbow flag will be carried during our walk against homophobia.
“Let’s walk all together against homophobia and transphobia under the rainbow flag. To free homosexuals will also free and heterosexuals.”
Last month police officers in Turkey raided the offices of a leading LGBT organisation on the pretence that “frequent visits by transgender people” were grounds to issue a search warrant.
Lawyers for the Lambda Istanbul Cultural Centre later discovered that an accusation had been lodged against the association for “participating in illegal prostitution activities, procuring transgender sex workers and sharing their earnings.”
More than a dozen plainclothes officers spent two hours at the centre.
“They examined the premises and all materials in the office, and also collected the identity cards of everyone who entered the centre,” a spokesperson for Lambda said.
“At the end of their search they were not able to find evidence of a criminal offence; however, they took with them some important documents regarding Lambda’s financial and membership systems.”
Government officials have made similar legal moves to shut down lesbian, gay, bisexual, and transgender organisations in Turkey but failed.
Kaos GL faced a demand for closure from Ankara’s deputy governor, Selahattin Ekmenoglu, in 2005. The closure petition was dismissed by prosecutors.
Turkey is a candidate country for EU membership, but concerns about human rights are one factor frustrating negotiations.
The chairman of Netherlands gay rights group COC, Frank van Dalen has called on the Dutch government to not support their application for EU membership until “basic human rights are fully respected by Turkey.”
The UK is a vocal supporter of Turkish membership.