The Maximality Principle (MP) states that for any first-order sentence φ in the language of set theory, if it is forced by a set forcing that φ is true in any further set generic extension, then φ must be true. The basic idea of MP was proposed by Chalons and its basic theory was developed by Hamkins. In this talk, we will discuss several variants of maximality principles and their relations with forcing axioms, bounded forcing axioms, and large cardinals. This is joint work with Nam Trang.