The Boston Gay Men’s Chorus is planning its next trip. The group, which toured Europe for the first time in 2005 and was the first gay chorus to perform in the Middle East last summer, will embark on a tour of South Africa in June 2018. “South Africa is a country of rich musical and choral traditions so we’re very excited to perform for audiences there and to honor those traditions,’’ Reuben Reynolds III, BGMC music director, said in a statement. “Because protest songs were an integral part of the anti-apartheid movement, South Africans believe deeply in the transformative power of music and its use as a tool to effect social change. BGMC was founded on those same beliefs and we hope our concerts will be received in that spirit.’’ The chorus is planning to perform a show in Cape Town to benefit PASSOP (People Against Suffering Oppression and Poverty), which provides support to LGBT refugees and asylum seekers.