Climate-driven changes in temperature, precipitation, snowpack duration, and streamflow are potentially altering alpine freshwater ecosystems, yet their long-term effects on freshwater macroinvertebrate assemblages remain unknown. We analysed a long-term dataset (1997-2020) from 16 alpine and sub-alpine stream sites near Thredbo and Perisher in the Snowy Mountains of NSW, to examine how hydroclimatic variables were associated with temporal changes in macroinvertebrate assemblage and functional structure relative to site-specific long-term baselines. Four response metrics were evaluated: Bray-Curtis deviation from each site’s long-term mean assemblage, EPT relative abundance, filter-feeder, and rheophily. Generalized additive models were used to assess macroinvertebrate associations with mean daily maximum temperature, precipitation, snowmelt timing (last snow day), and flow extremes, including interactions between low flow and broader climatic conditions. Assemblage responses were evident but modest. Assemblage similarity deviation from long-term mean assemblage structure increased slightly under wetter-than-average conditions. A significant interaction between low flow and last snow day showed that the ecological effects of low flow depended on snowmelt timing, with additional stream-specific low-flow responses. EPT relative abundance increased with precipitation, although this relationship was weakly non-linear and plateaued at higher precipitation values. Filter-feeder representation was higher under cooler-than-average conditions and declined with increasing temperature, whereas rheophily showed significant non-linear associations with both temperature and snowmelt timing. In contrast, several global smooth terms, including many low-flow and precipitation associations, were weak or not detected. Overall, these findings suggest that (sub-)alpine stream macroinvertebrate assemblages appeared relatively resistant to interannual hydroclimatic variability, while being more sensitive to seasonal phenology, warming, and stream-specific low-flow dynamics. This work supports the continuation of long-term studies of environmental change.