The Democratic Action Party (abbreviation: DAP; Malay: Parti Tindakan Demokratik‬; Chinese: 民主行动党; Tamil: ஜனநாயக செயல் கட்சி), is a major centre-left Malaysian political party which advocates social democracy and secularism. One of the component parties of the Pakatan Harapan (PH) coalition, it was an opposition party for 51 years until PH won the 2018 Malaysian general election and formed the federal government. However, before the coalition finished its first term, defections from partnering PH component parties caused it to lose power after 22 months, culminating in the 2020 Malaysian political crisis. As of 24 February 2020, DAP is the largest party in Malaysia's Dewan Rakyat.

The DAP usually draws much of their support from secular and liberal voters with a stable electorate from voters of big cities, coastal regions, professional middle-class, and working class. The party's strongholds are primarily in the urban and semi-urban areas of Penang, Perak, Selangor, Negeri Sembilan, Johor, Malacca and the Federal Territory of Kuala Lumpur. In the 2018 Malaysian general election, DAP contested in 47 federal constituencies and won 42 seats and 101 out of 104 state seats contested, most under the ticket of its ally People's Justice Party, representing a win rate of 95%, the highest among the major political parties contesting.