This study has developed the concept of Gender Power Sharing. The concept has been applied to construct Gender Power Sharing Index (GPSI) for thirty three developing countries of the world. The selection of countries is based upon the availability of the data of indicators used for the construction of GPSI. The index has been constructed by taking into account three different dimensions related with male and female„s relative participation in earning, spending and family size decision. The value of measure falls between 0 and 1, where 1 stands for perfect power sharing among male and female in major household concerns. While 0 shows an absence of sharing among male and female. Countries are ranked according to their standing in gender power sharing. GPSI has been found to be moderately correlated with existing gender indices such as Gender Development Index, Gender Inequality Index and Global Gender Gap. Temporal and spatial comparison of GPSI with other gender Indices show that some countries like Jordan and Egypt have low gender power sharing despite their relatively higher ranking in Gender Development Index. Similarly, some countries like Madagascar and Rwanda have higher Gender Power Sharing despite their low ranking in Gender Development Index. In next step, the role of Gender Power Sharing has been investigated to explain the differences of Economic Growth and Human Development across the selected countries. Our empirical findings indicate that gender power sharing as measured by GPSI has positive and significant effect on Economic Growth and Literacy. Among three different dimensions of gender power sharing the role of expenditure sharing has been found as the most important crucial for Economic Growth and Human Development.