<p>The youngest group of travellers, known as Generation Z (Gen Z), exhibits unique travelling and behavioral intentions toward sustainable tourism. Solo traveling, once considered unconventional, has gained popularity among Gen Z, driven by their desire for independence, authentic experiences, and environmental consciousness. However, limited research has explored how destination imagery and social media influences shape their solo travel intentions and pro-sustainable tourism behavior. This study addresses this gap by investigating the drivers of Gen Z solo travel behavior within a sustainability framework. Gen Z is selected for this research due to their distinct characteristics: digital fluency, environmental awareness, and strong trust on social media peer influence. As an emerging dominant force in global tourism, their choices are expected to reshape sustainable tourism practices. Recognizing this, the study examines the effects of destination image and nature-based destination image on solo travelling intentions, and further explores the moderating roles of gender and social media influencer trust. A quantitative methodology utilizing structural equation modelling (SEM) was employed on data collected from 588 solo Gen Z travellers. The findings reveal a strong positive relationship between solo travelling intentions and pro-sustainable behavior. Nature-based destination image proved to have a more significant impact than general destination image in influencing sustainable travel attitudes. Furthermore, social media influencer trust was found to significantly moderate the relationship between travelling intention and pro-sustainable behavior, though it showed no moderating effect between destination image and travel intention. The study offers important theoretical and practical insights for tourism marketers and policymakers in crafting sustainable travel strategies for Gen Z.</p>