This study investigated the relationship between exchange rate and inflation volatility and stock prices volatility in Nigeria, using time series quarterly data from 1986Q1-2012Q4. The volatilities of exchange rate and inflation in this study were calculated using standard GARCH(1,1) models. The relationship between exchange rate, inflation volatility and stock prices volatility was examined using GARCH(1,1)-S models of an extended GARCH-X models. The findings of the study show that there is a negative relationship between stock market prices volatility and exchange rate and inflation volatility in Nigeria. This result has an important implication for the investors and regulators in the stock market. Investors and regulators in the Nigeria stock market should take note of the systematic risks revealed by the exchange rate and inflation volatility when structuring their investment portfolios and diversification strategies as well as in formulating policies respectively.