In theory, yes. In practice, it is not always clear whether a reaction requires a spell slot.
Many reactions require you to expend a spell slot to cast the reaction. For example, you must expend a spell slot to cast the haste spell to increase the speed of a creature.
However, other reactions might not require a spell slot at all. For example, you can use your action to perform a reaction that requires no spell slots.
Some reactions might require you to expend more than one spell slot. For example, you must expend two spell slots to cast the shield of faith spell.