William Thomas Cahill (June 25, 1912 – July 1, 1996) was an American politician, lawyer, and academic who served as the 46th governor of New Jersey from 1970 to 1974.

Among his accomplishments as governor were new automobile emission standards, an increase in the sales tax from 3 to 5 percent, the introduction of the state lottery, and the passage of no-fault auto insurance.

The proposal was defeated in July 1972, but a state income tax was finally instituted four years later, after Cahill left office.

[1] During his final months as governor, Cahill named his predecessor, Democrat Richard J. Hughes, as chief justice of the New Jersey Supreme Court.

[6] After his term as governor, Cahill was a senior fellow at the Woodrow Wilson School of Public and International Affairs at Princeton University from 1974 to 1978.

Then-governor Christine Todd Whitman, and former governors Brendan Byrne, Thomas Kean, and James Florio were in attendance.

The William T. Cahill Center for Experiential Learning and Career Services at Ramapo College in Mahwah, New Jersey, was dedicated in his honor on September 10, 1997.