Riparian zones occur at the interface of aquatic and terrestrial ecosystems and are biologically diverse components of the landscape. Here, terrestrial arthropods support food webs as prey for birds, bats, reptiles, and other consumers, contribute to pollination and decomposition, and mediate energy and nutrient exchanges across ecosystem boundaries. Despite their key role, arthropods remain relatively understudied compared to vegetation and vertebrates, and restoration monitoring often emphasizes habitat structure or vegetation recovery while providing limited insight into ecosystem function. We evaluated how lateral position, vegetation structure, and stream restoration interact to shape riparian arthropod communities in montane streams of northern New Mexico. Using a before-after-control-impact (BACI) design, we sampled ground-dwelling arthropods across four distances from the stream (1-50 m) at sites restored using beaver dam analogs (BDAs) or plug-and-pond (P&P) treatments. Arthropods were identified to family and assigned to functional feeding guilds (spiders, non-spider predators, herbivores, detritivores). Sampling was paired with concurrent measurements of riparian vegetation structure and functional traits to evaluate habitat-mediated responses. Across sites, arthropod communities were strongly structured by lateral gradients. Total abundance, spiders, and detritivores declined with distance from the stream, whereas herbivores increased and non-spider predators peaked at the outer riparian margin. Vegetation structure—particularly canopy cover—explained additional variation beyond distance. Against this strong spatial template, BDA restoration produced clear responses, including increases in total abundance, family richness, spiders, non-spider predators, and detritivores, and declines in herbivores. In contrast, P&P restoration showed limited responses during a shorter post-treatment monitoring window. Where BDA effects occurred, they were not spatially uniform. Responses varied across the riparian corridor or depended on vegetation context, indicating reorganization across existing gradients rather than wholesale community reassembly. Riparian arthropods respond rapidly to restoration and provide sensitive, functionally informative indicators of riparian recovery. Yet, corridor-wide arthropod sampling is critical to fully capture restoration outcomes in coupled stream-riparian ecosystems.