This study empirically examines the pattern of domestic investment that is consistent with a neoclassical supply-side model of the Nigerian economy. The estimations are carried out with time-series data from 1970 to 2006 using the Johansen estimation techniques. The results conform to the findings of existing literature that real output, user cost of capital, and the level of financial development are significant determinants of domestic investment in Nigeria. The distinctive feature of the study is the significant role played by governance in explaining the long-term pattern of domestic investment in Nigeria. The results from the long-run estimation and the impulse responses revealed that a well-structured and stable socio-economic environment will boost domestic investment over the long run. Therefore, in modelling domestic investment for Nigeria, it is imperative to incorporate the significant role played by governance.