Xenopus embryos are particularly suited for functional experiments to investigate vertebrate embryonic development. Due to the large size of embryos and their development outside of the mother organism, they are very accessible, easy to manipulate, and allow for immediate observation of developmental phenotypes. Powerful methods have been established for both gain- and loss-of-function strategies, which build on these inherent advantages. This chapter describes injection methods used to overexpress gene products and inhibit gene expression as well as pharmacological approaches to manipulate Wnt signaling in Xenopus embryos.