In this book we tried to investigate the effect of different factors(independent variables)on Rwanda GDP (dependent variable) by using Classical Linear Regression Model (CLRM).We also checked whether there is no CLRM assumption which is violated.The study found strong positive correlation between some variables and Rwanda GDP but some variables don't have any effect on GDP and we have found the model which is adequate because the actual values and fitted values were moving together and residual was around mean zero and approximately constant variance and the coefficient of determination is very closer to 1.