The study examined the effect of monetary policy on credit supply to small and medium scale enterprises (SMEs) in Nigeria covering a temporal scope 1993 to 2018. It was modelled by using ratio of credit to SMEs to total credit (CSTC) as dependent variable while monetary policy rate (MPR), liquidity ratio (LQR), lending rate (LDR) and inflation (INF) were the explanatory variables. Secondary data were sourced from CBN Statistical Bulletin and the estimation was done using Auto regressive distributed lag (ARDL). The study found that monetary policy has negative and insignificant effects on credit supply to SMEs in the long run while in the short run, monetary policy has though insignificant positive but indirectly a significant positive effect through lending rate on credit available to SMEs. The implication is that, as MPR changes its effects are transmitted through lending rates of commercial banks to SMEs. Hence, the study concluded that monetary policy significantly and heterogeneously impacts on the credit supply to SMEs indirectly through lending rate in Nigeria. It was recommended among others that as the Central Bank of Nigeria continues to implement monetary policy in Nigeria, caution should be taken so that such decisions won’t be detrimental to businesses such as SMEs. In addition, MPR should be further reviewed downward in order to encourage SMEs from assessing more funds in Nigeria. Likewise, a pool of long-term funds should be created By Central Bank of Nigeria to bridge the financing gap of SMEs in Nigeria.