Small molecule inhibitors of neutral sphingomyelinase 2 (nSMase2) and their use for treating neurodegenerative diseases, such as, neurodegenerative diseases associated with high levels of ceramide, including, but not limited to Alzheimer's disease (AD), HIV-associated neurocognitive disorder (HAND), multiple sclerosis (MS), and amyotrophic lateral sclerosis (ALS), and, in other aspects, for treating cancer, are provided.