The use of renewable raw materials often improves the greenhouse gas balances of buildings over their life cycle compared to conventional building materials. This can be stated even if there are numerous definitional ambiguities regarding competing concepts of climate neutrality. Life cycle assessments (LCAs) can demonstrate the relative advantage of renewable building materials. In terms of resource availability and organic material flows, the increasing use of straw from various grains as a building material is promising. Agro-ecological arguments support field crops like miscanthus, hemp, and poplar. Bamboo, flax, cotton, coconut, pineapple, reed, bulrush, hops, jute, nettle, sugarcane, and wood from the kiri tree are also considered relevant as mass building materials for the construction sector. Biotechnologically advanced applications from the lignocellulose bioeconomy will impact the construction industry. In addition to solid wood, laminated and cross-laminated timber are playing an increasingly important role, expanding the raw material base to include hardwoods that have scarcely been used in construction until now. Structural modifications of wood on the micro or nano level are also becoming relevant. This chapter provides an introductory overview.