<p>Accurate characterization of high-frequency ground-motion attenuation and site response is crucial for seismic hazard assessment; however, such information remains limited for the Garhwal Himalaya despite its high seismic potential. Previous Himalayan studies have generally addressed either the spectral decay parameter κ or site response independently, and systematic evaluations linking site-specific κ_₀ with amplification characteristics are scarce for this region. This study aims to jointly quantify κ and site response characteristics and to assess the potential of κ_₀ as a proxy for site amplification in data-scarce Himalayan regions. A dataset comprising 432 three-component strong-motion records from 40 earthquakes (M_w 3.0—6.5) recorded at stations with varying site conditions is analyzed. κ values are estimated using the Anderson-Hough method for horizontal and vertical components, and station-specific κ₀ values are derived from κ-distance regression. Site response is independently evaluated using the Horizontal-to-Vertical Spectral Ratio technique. The results indicate mean κ values of 0.066 for horizontal components and 0.045 for the vertical component, with κ increasing with hypocentral distance and showing no clear magnitude dependence. κ₀ varies from 0.03 at hard-rock sites to 0.097 at soft-soil sites, reflecting strong site control. HVSR analysis reveals predominant frequencies of 1.20–5.78&#xa0;Hz and amplification factors of 4.37–13.09, with higher amplification at soft-soil stations. The observed correspondence between κ₀ and HVSR amplification suggests that κ_₀ effectively captures relative site response. These findings provide improved constraints on high-frequency attenuation and site effects in the Garhwal Himalaya and have important implications for seismic hazard assessment and earthquake-resistant design.</p>