The 20 Party Alliance was a Bangladeshi big tent political coalition led by the Bangladesh Nationalist Party (BNP). It was originally formed as the 18 Party Alliance on 18 April 2012 in Dhaka, extending its predecessor the 4 Party Alliance. The 18 Party Alliance was formed in an effort to strengthen the opposition's demands for restoring the caretaker government system used between 1996 and 2008. The main rival of this alliance is the Grand Alliance, led by Awami League, which came into power after the election in 2008.
The Four Party Alliance was formed in 1999 ahead of the 2001 General Election, and consisted of the Bangladesh Nationalist Party (BNP), Jamaat-e-Islami, Jatiya Party (Naziur) and Islami Oikya Jote. The alliance won a substantial majority in 2001, but was heavily defeated by the Awami League-led Grand Alliance in 2008. On 18 April 2012, the Four Party Alliance was extended and took the new name "18 Party Alliance".