Mary Mitzi Lim Cajayon-Uy (born May 6, 1978), also known as Mitch Cajayon-Uy, is a Filipino politician who is the incumbent representative from the 2nd District of Caloocan in the House of Representatives of the Philippines since 2022 and previously from 2007 to 2013. She also served as the executive director of the Council for the Welfare of Children, an attached agency of the Department of Social Welfare and Development from 2017 to 2021. She also served as a city councilor of Caloocan.

Prior to joining politics, Cajayon was named as Miss Caloocan in 2000. She then joined politics as a city councilor of Caloocan from the 2nd district, serving for one term from 2004 to 2007.^[1] She was then elected as representative of the 2nd district of Caloocan in 2007; she was re-elected in 2010. In 2009, she was awarded the Award for Congressional Legislative and Service Excellence by the Consumers League of the Philippines Foundation, Inc.^[2]

She was appointed the executive director of the Council for the Welfare of Children, an attached agency of the Department of Social Welfare and Development, having been appointed to the post by President Rodrigo Duterte in July 2017.^[3] She resigned from the position to run once again for representative at the 2nd district of Caloocan in 2022;^[4][5] she later won the race.^[6] On November 12, 2021, she was acquitted by Sandiganbayan of graft and malversation charges in relation to the alleged misuse of ₱10 million in Priority Development Assistance Fund for supposed ghost projects in 2009.^[7]