Walter Kenneth Martinez, Sr. (November 16, 1930 – May 11, 1986) was an American attorney and politician who served as a member of the New Mexico House of Representatives.

Martinez was born in Tierra Amarilla, New Mexico, one of eleven children in poor but well-educated family.

[2] He became a general legal practitioner with the firm of Tibo Chavez and Boucher and established an office in Grants, New Mexico.

[4] That had begun to change after the Supreme Court "one man, one vote" decision in Baker v. Carr (1962), which forced electoral districts to be more balanced in size and led to growing numbers of liberal Hispanic and urban intellectual representatives.

[9][b] Martinez and Joseph Fidel worked together to obtain funding for many projects in the Grants area.

[3] His eldest son, W. Ken Martinez, served as a member of the New Mexico House of Representatives from 1998 to 2016.

[12] Martinez was diagnosed with Amyotrophic lateral sclerosis (Lou Gehrig's disease) and left the House in 1984.