Electrons are fundamental particles, meaning they are not made up of smaller particles. They are one of the basic building blocks of matter, along with quarks (which make up protons and neutrons).

So, the answer to "what are electrons made of?" is nothing smaller. They are considered point-like particles, meaning they have no internal structure.

However, it's important to note that our understanding of fundamental particles is constantly evolving. We may discover new theories or evidence that reveals a deeper level of structure within electrons.