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Abstract This paper presents the results of an integrated sequence stratigraphy approach using seismic, well log and biostratigraphic data to build sequence stratigraphic framework and its implication in petroleum system understanding for the southwestern part of the Malay Basin. Seismic data were used to interpret third order Sequence Boundaries (SB) and Maximum Flooding Surfaces (MFS) based on reflector terminations. Well log analyses were carried out to support the interpretations and were cascaded down to define the third order sequences and associated system tracts (LST, TST and HST). Biostratigraphic data were also used to validate the SB, MFS and the paleo-environments. This study has subdivided the sedimentary successions into six 3rd order sequences namely Sequence 1 to Sequence 6. Each of the sequence is bounded by sequence boundary, which has been calibrated with the Malay Basin Chronostratigraphic Chart (PETRONAS, 2007). Two source rocks are present for the study area- the deeper synrift section with source rocks deposited in a lacustrine environment (Late Oligocene age) and the shallower source rock deposited in a marine inner neritic environment (Early Miocene age). The migration pathway for the deeper section is through faults, and from lateral migration for the shallow section. The study also indicates that the potential reservoirs are thinning basinward (southwest to northeast). The potential reservoirs are interpreted to be the fluvial, lacustrine and shallow marine sands. Data from several key drilled wells suggests that reservoir is at low risk in the sand-prone areas of the southeastern part compared to the northern part which is more shale-prone. Based on the present study, it is inferred that trap integrity is the main risk for petroleum system. While a good top seal is provided by the main regional shales in deeper section, the seal at the shallow sections are from thin and discontinuous intra-formational shales that are present in every sequence. The presence of younger faults cutting through the reservoir may cause the potential for hydrocarbon leakage. The present study has identified five potential plays and also established the regional sequence stratigraphic framework in southwestern of Malay Basin.