Erosion-induced land degradation remains a persistent barrier to agricultural productivity and sustainability for smallholder farmers in Africa, where rapid population growth has intensified land pressure, especially in Ethiopia. Despite the implementation of several sustainable land management (SLM) initiatives, sustaining farmers' motivation and voluntary adoption remain problematic. This study examined the determinants of farmers' intention (INT) to adopt three SLM technologies-compost making, forage planting, and soil bund making-using an extended theory of planned behavior framework. A measurement model incorporating psychological constructs and contextual factors was developed and tested via partial least squares-structural equation modeling based on data from 202 respondents in the Ethiopian highlands. Attitude (ATT) significantly influenced adoption INT across all technologies (β = 0.38-0.64), while Perceived Behavioral Control (PBC) was crucial for forage (β = 0.43), a recently introduced practice. Subjective Norms affected INT indirectly through influencing PBC and ATT for compost and forage (β = 0.25-0.28). Interpersonal information-primarily from extension officers, relatives, and other farmers-emerged as the strongest contextual influence (β = 0.21-0.26), whereas access to media-based information was limited. Mobile phone ownership, experience with the SLM practices, prior-year profits, and land size had technology-specific effects. The findings provide practical insights to inform SLM promotion strategies through situational assessment and targeted interventions that enhance farmers' awareness and motivation for voluntary adoption.