Indonesia, as one of the world’s megabiodiversity countries, faces a severe ecological crisis characterized by massive deforestation, pollution, and climate change impacts, which threaten both ecosystems and human livelihoods. This crisis occurs alongside the national vision of Indonesia Emas 2045 outlined in the RPJPN 2025–2045, which emphasizes sustainable development and environmental resilience. However, the dominant anthropocentric ecclesiology in Indonesian churches has proven inadequate in responding to the cry of the earth. This article proposes the biblical concept of oikos (household of God) as a central metaphor for reconstructing an ecological ecclesiology. Through a contextual systematic theological approach and library research, this study dialogues global ecological theologies (McFague, Boff, Conradie, Laudato Si’) with Indonesian local wisdom, including Archipelagic Ecotheology, Toba Batak cultural capital, stilt-house metaphors, and eco-literacy movements. The findings show that understanding the church as oikos and oikos as the church enables the transformation of the church from an anthropocentric institution into an ecological community that actively promotes environmental justice. This reconstruction offers practical implications for ecological conversion, eco-literacy education, interfaith leadership, and policy advocacy, positioning the church as a strategic partner in realizing environmental justice within Indonesia’s Golden 2045 vision.