Passaic County Technical Institute (also known as PCTI, Passaic County Tech, Wayne Tech or simply Tech), is a vocational public high school in Wayne, that serves students in ninth through twelfth grades from all of Passaic County, in the U.S. state of New Jersey. It is located near the city of Paterson. PCTI offers some vocational classes in addition to several college credit courses. It is the sister school of the Diana C. Lobosco STEM Academy, with which it shares a campus and extracurricular programs.

As of the 2023–24 school year, the school had an enrollment of 3,660 students and 302.0 classroom teachers (on an FTE basis), for a student–teacher ratio of 12.1:1. There were 1,483 students (40.5% of enrollment) eligible for free lunch and 328 (9.0% of students) eligible for reduced-cost lunch. Based on 2021-22 data from the New Jersey Department of Education, PCTI was the largest high school in the state, one of 29 schools with more than 2,000 students.

Schooldigger.com ranked the school 212th out of 376 public high schools statewide in its 2010 rankings (an increase of 21 positions from the 2009 rank), which were based on the combined percentage of students classified as proficient or above proficient on the language arts literacy and mathematics components of the High School Proficiency Assessment (HSPA).

In 1917, a group of businessmen in Paterson helped form Paterson Vocational School to train young men to enter the textile industry. The school accepted boys who were at least 14 years of age or in the sixth grade, and trained them for two years or until they were ready to assume a job in a factory or trade. From 1917 to the early 1940s, Paterson Vocational School continued to operate as a two-year school, gradually expanding its curriculum to include a wider variety of trades. During World War II, the school remained open around the clock providing men and women with the training to become machinists and draftsmen to design and construct the engines used in bombers, fighters and transport aircraft flown in the Pacific and European theaters. For its service, the school was honored by the War Department.

Aware of the part technology would play in the booming postwar economy, Paterson Vocational School applied for and received approval from the New Jersey Department of Education to become a full-fledged high school in 1946. Academic subjects were added, as were new trades like Refrigeration, Industrial Electric, and Electronics. The school was renamed Paterson Technical and Vocational High School and quickly gained the name Paterson Tech. Agriculture was offered to shared-time students attending Central High School (now Kennedy High School), with Paterson Tech renting a farm close to PCTI's present Wayne site, where students learned to raise farm animals and grow crops.

By the 1960s, the importance of vocational and technical education was becoming obvious, and in 1964, Paterson Mayor Frank X. Graves Jr. turned over Paterson Tech to the Passaic County Board of Chosen Freeholders, thereby providing all youngsters in Passaic County access to Passaic County Technical and Vocational High School. With students flooding in from all over the county, Passaic County Tech, now reaching a student population of 500 young men and one girl, was significantly overcrowded. The school's two buildings — one dating from the Civil War located at the corner of Summer and Ellison, the other a refurbished factory on Market Street — could not meet the demands. By 1965, plans were well underway to build a new school that would accommodate students for generations to come.

Provided with a Federal grant of $3,925,000 (equivalent to $40.1  million in 2025) — the largest ever awarded to that date — and research from a Citizens' Study Committee, the county chose a 59-acre (240,000 m²) tract of land which it owned in Wayne, previously the site of Camp Hope.

Groundbreaking ceremonies were held in November 1966, and construction began 15 months later. On September 8, 1970, Passaic County Technical and Vocational High School — at the time, the largest technical/vocational high school in the state and third largest in the nation — opened its doors to close to 1,500 young men and women. In the 25 years since, PCTI has added two wings and an additional Special Needs building, a variety of academic courses and special programs, and has kept abreast of technological advances and economic trends by constantly updating vocational, occupational, and technical courses. Passaic County Tech has since been renamed Passaic County Technical Institute.