•Long-term changes in green infrastructure and urban expansion were assessed.•Population and economic growth were the main drivers of observed changes.•Climate and latitude were not the main factors behind green infrastructure changes.•Loss and fragmentation of GI were linked with urban expansion and lack of planning. Green infrastructure (GI) contributes to environmental quality and human well-being in urban environments by providing a number of ecosystem services. There is evidence that urban expansion negatively impacts on GI, but most studies have focused on large cities at the expense of an understanding of these processes in smaller cities. Here we assess the urban expansion and spatio-temporal dynamics of GI in small and medium-sized Chilean cities over a period of three decades. Seven cities were selected along a latitudinal gradient extending from 23 °S to 45 °S, and covering a wide variety of climates including: arid, semi-arid, mediterranean and temperate. Remote sensing and landscape analysis techniques were employed to assess changes in urban areas and GI spatial patterns. The cities that were analyzed showed a continuous expansion over the last 30 years associated with high population growth rates. Landscape analysis also evidenced an increasing level of GI fragmentation in most cities. Population growth, economic growth, and public policies seem to have a greater influence on long-term changes in GI than climate or geographic location. Our study highlights the need for better urban policies that protect and develop GI because of its crucial role in human well-being and urban sustainability.