Mark M. Lowenthal (born September 5, 1948) is an author and adjunct professor at the Krieger School of Arts and Sciences at Johns Hopkins University in Baltimore, Maryland.

In 2005, Lowenthal retired from a prolific career working with the United States Intelligence Community and a recognized national security affairs expert.

Upon his retirement, he was commended for his work and commitment to the intelligence community by New Jersey Congressman Rush D. Holt Jr., in the U.S. House of Representatives.

Lowenthal is a notable contestant on the American game show Jeopardy!, appearing five times, including winning the "Tournament of Champions" in 1988.

[4] In 1992, he co-wrote Secrets of the Jeopardy Champions, which was marketed as an instruction manual for prospective contestants of the trivia game show.

As the ADCIAP, Lowenthal was one of the key coordinators and evaluators of the National Intelligence Estimate on Iraq leading up to Operation Iraqi Freedom.

In a 2009 Op-Ed in The Washington Post, Lowenthal vehemently defends the protection he and his office extended to the product from the forces of politicization: The 2002 estimate claiming that Iraq possessed weapons of mass destruction had little influence on anyone's decision about going to war.

He called into question the ability of technological solutions like Intellipedia and A-Space to resolve some of the most pressing reforms in the community.

[10] Lowenthal was quoted as saying, "I think, unfortunately, a lot of this is pandering to a bunch of commissions that have no understanding of what we do for a living, or the nature of our work, and to a workforce.

[4] He returned for the quarterfinals of the Battle of the Decades, and was matched up against 2009 Grand Champion Dan Pawson and all-time money winner Brad Rutter.