Technological innovation is central to the development and scaling of fintech startups, yet its relationship with organizational growth remains insufficiently understood among early-stage ventures in emerging markets. This study investigates how technological innovation capabilities are associated with organizational growth in early-stage fintech startups, drawing on the technological dimension of the Technology–Organization–Environment (TOE) framework. Technological innovation was examined through product innovation, scalable digital technologies, systems integration, and cybersecurity. A positivist research approach combining descriptive and explanatory designs was adopted. Data were collected through structured questionnaires from founders, co-founders, and senior managers of early-stage fintech startups in Nairobi City County, Kenya. A total of 104 valid responses were obtained from a sample of 131 startups drawn from a target population of 195 firms. The data were analyzed using descriptive statistics, Pearson’s correlation analysis, and simple linear regression. The results showed a positive and statistically significant relationship between technological innovation and organizational growth (unstandardized regression coefficient B = 0.43, standardized regression coefficient β = 0.36, t-statistic = 3.90, probability value p < 0.001). Technological innovation explained 13.0% of the variance in organizational growth, with a coefficient of determination (R²) of 0.130, indicating that technological capabilities were associated with growth while leaving substantial variation attributable to other organizational and environmental conditions. The findings indicate that technological innovation constitutes an important organizational capability for early-stage fintech startups, particularly through continuous product development, scalable digital infrastructure, systems integration, and cybersecurity. This study provides firm-level evidence linking technological capabilities with entrepreneurial growth and shows how the technological dimension of the TOE framework can be applied to understand organizational outcomes in technology-intensive new ventures.