The Massachusetts legislature has amended its state anti-discrimination law to prohibit discrimination based on gender identity in employment, insurance, housing, lending, credit and education. The legislation also expanded the state hate crimes law to cover gender identity. The law, entitled An Act Relative to Gender Identity, also referred to as the Transgender Equal Rights Bill, was signed into law by Governor Deval Patrick on November 23, 2011 and becomes effective on July 1, 2012.

Gender identity, as defined in the new law, refers to "a person's gender-related identity, appearance or behavior whether or not that gender-related identity, appearance or behavior is different from that traditionally associated with the person's physiology or assigned sex at birth." In order to qualify for protection from discrimination based upon gender identity, transgender individuals may demonstrate their gender-related identity with evidence including their medical history, care or treatment of their gender-related identity, a consistent assertion of their gender-related identity, or any other evidence that gender-related identity is part of his or her core identity.