Over the past decade, there has been a significant increase in research studies that introduce contemplative practices -- such as mindfulness, compassion, and lovingkindness -- into the educational setting. While these programs have shown promising results for both students and teachers, there remains a gap in understanding how to integrate contemplative practices into the curriculum of teacher training education for sustainability. This paper aims to present a conceptual framework of Contemplative Practices (CP) that focuses on lovingkindness-compassion, which has the potential to revolutionize teaching practices towards sustainability. By advocating for the urgent integration of CP within the curriculum of teacher training education for sustainability, this paper asserts that nurturing the lovingkindness-compassion competency can pave the way for a sustainable curriculum and a curriculum for sustainability.