Extending across seven countries, the Alps represent an important element for climate and atmospheric circulation in Central Europe. Its complex topography affects processes on different scales within the atmospheric system. This is of major relevance for the decadal trends in Surface Solar Radiation (SSR), also known as Global Dimming and Brightening (GDB). In this study we analysed data from 14 stations in and around the Swiss and Austrian Alps, over a period ranging from the 1960s up to the 2010s, with the aim of characterizing the spatio-temporal variations of the GDB and understanding the causes for such trends in this region. Our results showed a different behavior in the SSR decadal trends in the western part of the Alps in comparison to the eastern part. We also identified a remarkable difference between the causes of such trends in the stations at low altitudes in comparison to the station at higher altitudes. The SSR trends under cloudy conditions revealed strong evidence for a control of the decadal trends by cloud optical depth at high elevation sites, in contrast with a strong clear-sky forcing at low elevations. Results from previous literature and available data suggest that such phenomena could be associated with the indirect and direct aerosol effect, respectively, due to differing pollution levels.