Over the past two decades, the concept of connectivity has been used to describe and quantify various factors affecting fluxes of water and sediments at different classes. Changes in land use and land cover affect the hydrological connectivity and therefore influence hydrological processes such as the rainfall-runoff response and sediment redistribution. The objective of this study was to assess the effect of long-term (85 years) land use/cover changes on the hydrologic connectivity and the rainfall-runoff response in a semi-arid catchment. Land use/cover changes between 1935 and 2020 of the canyon-like Tsili catchment (27.5 km²) in the Tigray region (Ethiopia) were mapped for 1935, 1967, 1994 and 2020. The Soil & Water Assessment Tool (SWAT) was used to model rainfall-runoff responses for the land cover at four time steps for two scenarios. In the first scenario the goal was to study the impact of rainfall variability based on different precipitation data (CFSR and TAMSAT). In the second scenario only the effect of land cover change was analysed, by using the same climate for the four land covers. As river discharge measurements are not available, peak discharges were estimated by determining the riverbank width for every time period. The relative importance of topography derived hydrological connectivity and land use/cover as drivers affecting runoff response was analysed using multiple linear regression models. Over the last 85 years agricultural land expanded considerably, at the expense of mostly shrubland and forests. In the course of the 20th century grasslands more than doubled, but decreased thereafter. Settlements increased little. Mean river bank width increased from 7.6 m in 1935 to 10.4 m in 2020. In the first scenario, SWAT simulations based on CFSR data resulted in higher simulated precipitation with associated higher surface runoff than the simulations based on TAMSAT data. Simulations of the second scenario show increases in simulated surface runoff for each time period, which can only be attributed to land cover change. Runoff coefficients also increased indicating an increased hydrological connectivity. A strong correlation between the simulated annual surface runoff and river bank width was found for the four time steps. The results from the regression models indicate a great significance of both hydrological connectivity derived from topography and land use/cover change as variables in explaining surface runoff in this catchment. The overall results indicate an increase in runoff response and hydrological connectivity related to land use/cover change in the Tsili catchment over the last 85 years.