电子绕射，是指电子在通过某些障碍物时发生衍射的现象。因为波粒二象性的存在，电子也可被当做是波，从而也能产生衍射现象。电子的波长满足德布罗意波长公式：

h表示普朗克常数，p表示动量。由于电子的动量较光子大得多，因而其波长也短得多。所以想使电子发生衍射时就需要更微小的障碍物，实验上一般是采用晶体。另外，正是由于电子比光子更难发生衍射，电子显微镜的分辨率比光学显微镜的更高。

当电子波穿过晶体的时候，被晶体中的原子散射，散射的电子波互相之间干涉所产生的现象就是电子衍射。晶体中每个原子均会对电子进行散射，使得波长和方向发生变化。并且部分电子会与晶体中的原子发生能量交换作用，若电子波长发生变化，则称为非弹性散射；若没有波长变化，则称为弹性散射。

Electron diffraction refers to the wave nature of electrons. However, from a technical or practical point of view, it may be regarded as a technique used to study matter by firing electrons at a sample and observing the resulting interference pattern. This phenomenon is commonly known as wave–particle duality, which states that a particle of matter (in this case the incident electron) can be described as a wave. For this reason, an electron can be regarded as a wave much like sound or water waves. This technique is similar to X-ray and neutron diffraction.