Brunei Darussalam is a dire necessity to develop Islamic banking system due to this is Muslims country which has diverse readiness such as capital market together with political aspects, these can stimulate to current Islamic banking system in the international as Muhammad, Yasir and Khalid (2014) had studied to estimate and analyze the Islamic banks efficiency in South Asian Countries. Stochastic frontier approach is used to estimate the performance through input and output method for the period of 2004 to 2011. Results demonstrate that Islamic banking is efficient about 98.19% with respect to return on asset ratio; with respect to return on equity ratio is about 91.4% and 77.03% with respect to net profit ratio. As per the efficiency-ranking measurement, Brunei stands at top followed by Pakistan, Iran and Bangladesh among the South Asian countries.