Development of an understanding of membrane nanodomains colloquially known as "lipid rafts" has been hindered by a lack of pharmacological tools to manipulate rafts and protein affinity for rafts. We screened 24,000 small molecules for modulators of the affinity of peripheral myelin protein 22 (PMP22) for rafts in giant plasma membrane vesicles (GPMVs). Hits were counter-screened against another raft protein, MAL, and tested for impact on raft , leading to two classes of compounds. Class I molecules altered the raft affinity of PMP22 and MAL and also reduced raft formation in a protein-dependent manner. Class II molecules modulated raft formation in a protein-independent manner. This suggests independent forces work collectively to stabilize lipid rafts. Both classes of compounds altered membrane fluidity in cells and modulated TRPM8 channel function. These compounds provide new tools for probing lipid raft function in cells and for furthering our understanding of raft biophysics.