Loneliness is a critical issue among older people and poses a significant risk factor for various physical and mental health conditions. While recent wearable technologies can monitor behavioral and physiological changes associated with loneliness, existing solutions such as accelerometers and inclinometers often lack comfort and flexibility for long-term monitoring. Smart textile systems offer a viable solution for continuous monitoring by integrating sensors and conductive materials into textiles. However, there remains a critical technological gap that no existing solution integrates multimodal textile-based sensing specifically for loneliness detection. This review addresses that gap by providing a comprehensive review of smart textile technologies for monitoring loneliness in older people, highlighting sensing and design innovations to meet the needs of older users. We explore key behavioral patterns and physiological symptoms associated with loneliness and review suitable wearable sensing technologies, focusing on textile-based solutions that combine comfort, flexibility, and monitoring accuracy. In addition, we examine current advances in data collection, transmission, and analysis for smart textile systems, exploring their potential and challenges in the field of elderly care. By identifying specific design requirements and challenges for monitoring loneliness in older people, this review lays the foundation for future research and development of proactive loneliness detection and intervention.<p></p>