This paper, based on two engineering industry SME case studies, traces the origin and process of technological innovations enabling the development and introduction of new products leading to market expansion and enterprise growth. The study throws light on how entrepreneurs played a decisive role in recognizing market opportunities, building up crucial in-house technological capability, supplementing it with appropriate external assistance, to carry out technological innovations. A constant interaction with its customers is in-built into the system. As a result, the SMEs could achieve successful product innovations leading to their gradual growth, over time. Finally, based on the observations and inferences derived out of the two cases, a theoretical construct of the growth of innovation in SMEs is postulated. This is done linking the three stages of their development: (i) start-up and stabilizing, (ii) building up technological capability and implementing innovations; and (iii) opening up of new markets resulting in firm growth.