Methylamphetamine may refer to:
- Phentermine, α-methylamphetamine
- 2-Phenyl-3-aminobutane, β-methylamphetamine
- Methamphetamine, N-methylamphetamine
- Methamphetamine hydrochloride, "crystal meth"
- Ortetamine, 2-methylamphetamine
- 3-Methylamphetamine
- 4-Methylamphetamine