The predecessor union of NABET, the Association of Technical Employees (ATE), was founded in 1934. The National Broadcasting Company (NBC) formed the ATE as a company union, in an effort to prevent their employees from being organized by the International Brotherhood of Electrical Workers (IBEW). The ATE would not stay under NBC control for long. It began an energetic organizing campaign, and in 1940 changed its name to the National Association of Broadcast Engineers and Technicians (NABET).

During this period, NBC owned two national networks, designated Red and Blue. In the early 1940s the Federal Communications Commission ordered NBC to divest some of its holdings, and NBC sold the Blue network, which soon became the American Broadcasting Company (ABC). NABET retained the right to represent the professional employees of ABC.

In 1951, in the midst of a jurisdictional dispute with the IBEW and looking for allies, NABET joined the Congress of Industrial Organizations (CIO). The CIO gave NABET a charter to organize all broadcast industry employees. To reflect this broadening of representation, the union changed its name to the National Association of Broadcast Employees and Technicians and began to organize non-professional workers.

Shortly after its affiliation with the CIO, the NABET-IBEW dispute came to a head over organizing the Columbia Broadcasting Company (CBS). The CBS disagreement was brought before the National Labor Relations Board (NLRB). The Board ruled in favor of the IBEW, which was given authority to organize CBS technical employees.

In 1967 the Hollywood and New York City locals led a fight to strengthen the authority and autonomy of local NABET organizations. This dispute nearly destroyed the union, but resulted in constitutional changes that increased the influence and independence of the network locals.

NABET led ABC national network employees through a strike in 1977. Again in 1987, the NABET workers struck, this time on behalf of the NBC national network. Throughout the late 1970s to the mid-1990s NABET continued to organize local networks and affiliate stations.

In 1993 NABET became affiliated with the Communications Workers of America (CWA). In 1994 NABET and CWA held a conference on the possibility of solidifying their affiliation with a formal merger. The conference was a success, and in 1994 NABET merged with CWA. The union once again changed its name, becoming NABET-CWA. NABET-CWA currently represents over 10,000 workers in the broadcast industry.