Foundation and Bootstrap are both popular front-end frameworks, but they differ in several ways. Foundation is created by Zurb and uses Sass, while Bootstrap is created by Twitter and uses LESS. Their grid systems both use 12 columns and are responsive, but Foundation has more breakpoints defined by default. Some key components also differ between the frameworks, like Orbit vs Carousel and Magellan vs Scrollspy. Both frameworks are highly customizable but Foundation provides more options out of the box.