Gender is one of the most permeating aspects of human life. On an individual level, it affects how we think, feel and behave. On a social level, it affects legislation, healthcare, labor market, politics, education, and everyday life. However, there are many misconceptions about gender that negatively impact all of us, regardless of whether we are aware of its influence. In the past twenty years, trans* people have been increasingly discriminated against based on an aspect of their gender, called gender identity. Gender identity is an individual’s inner sense of their gender, which may be the same as or differ from the sex they were assigned at birth. While some people are supportive of the term and trans* people’s fight for basic human rights, others oppose it. By looking at several gender theories, their roots, foundations and arguments, this thesis analyzes gender and gender identity from a philosophical perspective. It provides critiques of the traditional binary gender theory, and counterarguments to movements and groups which surfaced as backlash against trans* people and gender identity. Finally, this thesis suggests an account of gender identity that should be adopted to ensure that all individuals – regardless of their anatomy and gender identity – are recognized, protected and supported in all aspects of society.