* Comparative: less
* Superlative: least
It's important to note that "little" can be used both as an adjective and an adverb. When used as an adjective, it means "small in size or amount." When used as an adverb, it means "not much" or "to a small degree."
The comparative and superlative forms, "less" and "least," apply to both the adjective and adverb uses of "little."