The BNP is holding a rally at Suhrawardy Udyan to mark the National Revolution and Solidarity Day.
BNP Chairperson Khaleda Zia will address the rally through a video conference.
Senior leaders of the party started joining the rally early afternoon on Thursday.
Earlier in the morning, Khaleda Zia placed a wreath at the grave of party founder Ziaur Rahman.
On November 7 in 1975, Ziaur Rahman came out of house arrest and took over as the new military chief.
In 1975, Zia became the first military ruler of Bangladesh after a period of political turmoil following the August 15 assassination of Bangabandhu Sheikh Mujibur Rahman and his family.
