Both mezcal and tequila are Mexican spirits made from the agave plant. However, while not all mezcal is tequila, all tequila is mezcal.
Answer: True.
While many think mezcal is a type of tequila, the opposite is true. Any distilled spirit made from the agave plant is considered mezcal (the name itself comes from the Aztec word mexcalli, or "cooked agave"). Tequila, however, must specifically be made from the blue agave plant.