Tropomyosin receptor kinase B (TrkB) signaling plays a critical role in neuronal cell survival, proliferation, and differentiation. Dysregulated TrkB signaling is implicated in neurodegenerative diseases and cancers. TrkB signaling can be precisely modulated via emerging optogenetic approaches based on light-inducible protein-protein interactions. This chapter discusses the application of different optogenetic strategies in activating TrkB signaling based on photosensitive proteins including Arabidopsis thaliana cryptochrome 2 and Vaucheria frigida light-oxygen-voltage domain. It also includes protocols on using light to activate TrkB signaling, upregulate downstream signaling pathways, and promote the differentiation of neuron-like PC12 cells.