In the previous chapters we saw that silicene monolayers can be grown epitaxially on Ag(111) surfaces having various reconstructions and electronic structures. In this chapter, the adsorption of molecules on silicene grown on Ag(111) is reviewed based on theoretical and experimental work. We firstly introduce the thermodynamics and kinetics associated with adsorption on silicene, which is determined by the low-buckled structures. The typical adsorption methods for modifying the physical and chemical properties of silicene, including oxidation and hydrogenation are reviewed in Sect. 11.2. The unique adsorption process corresponding to various types of adatoms, including alkali and metal adatoms is discussed in detail in Sect. 11.3. The effects of adsorption on the electronic structure and chemical properties of silicene are important for the development of its applications, which is discussed in Sect. 11.4. We conclude the chapter with the future research directions.