NORTHROP GRUMMAN CORPORATION

EXHIBIT 15

LETTER FROM INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

July 26, 2023

The Board of Directors and Shareholders of Northrop Grumman Corporation

Northrop Grumman Corporation

2980 Fairview Park Drive

Falls Church, Virginia 22042

We are aware that our report dated July 26, 2023, on our review of the interim financial information of Northrop Grumman Corporation and subsidiaries appearing in this Quarterly Report on Form 10-Q for the quarter ended June 30, 2023, is incorporated by reference in Registration Statement Nos. 033-59815, 033-59853, 333-67266, 333-100179, 333-107734, 333-121104, 333-125120, 333-127317, and 333-175798 on Form S-8, 333-270497 on Form S-3, and 333-264549 on Form S-4.

/s/ Deloitte & Touche LLP

McLean, Virginia