The funeral is open to the public.
Schlafly died Monday at 92.
Trump praised the early supporter of the Religious Right Friday while speaking at the Values Voter Summit in Washington.
"Phyllis fought very hard to the very end for a free and prosperous America," he told the audience. "She understood that to be truly united as a country, we can't simply turn to government or politicians."
"Phyllis endorsed me at a time when it was not necessarily the thing to do, even the popular thing to do, and I will never forget that that had a great, great impact," Trump added. "I look forward to being with her family tomorrow."
Schlafly was most well-known for her work opposing the Equal Rights Amendment in the 1970s, emerging as one of the leading female critics of the feminist movement.
"Phyllis Schlafly is a conservative icon who led millions to action, reshaped the conservative movement, and fearlessly battled globalism and the 'kingmakers' on behalf of America's workers and families," Trump said following her death. "I was honored to spend time with her during this campaign as she waged one more great battle for national sovereignty."
In her latest book -- "The Conservative Case for Trump" -- released Tuesday, Schlafly argued that conservative Christians should follow high profile evangelical leaders, including Liberty University President Jerry Falwell Jr. and Family Research Council President Tony Perkins, and support Trump's candidacy.
"Trump has gone to great lengths to court national leaders in the social-conservative movement and has convinced many of the most prominent ones that he genuinely supports their policy positions," she wrote in the book co-authored by Ed Martin and Brett M. Decker.
Trump, who is handily winning with evangelical voters according to the most recent Pew poll, will protect the Christian faith from Muslims abroad and the political left in the US, Schlafly and her co-authors wrote.
"Christianity is under attack around the world -- most dramatically from Islamists, but also insidiously here at home with attacks on religious freedom," they wrote. "Donald Trump has made a point about speaking out against the persecution of Christians abroad and against the left's political correctness that is trying to ban public expressions of Christianity at home."
"Trump is also outspoken on the need to defend Christians in Muslim countries and other countries where they are persecuted," they added.