FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2023 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For transition period from __________ to __________ Commission File Number: 001-35791 Northfield Bancorp, Inc. UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 (Exact name of registrant as specified in its charter) (State or other jurisdiction o ...