UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-K Large accelerated filer ☒ Accelerated filer ☐ Non-accelerated filer ☐ Smaller Reporting Company ☐ ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934, for the Fiscal Year Ended December 31, 2019, or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934, for the transition period from N/A to . Commission File Number: 0-23695 BROOKLINE BANCORP, INC. (Exact nam ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q (Mark One) ☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2019 OR ☐TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from N/A to . Commission file number 0-23695 BROOKLINE BANCORP INC. (Exact name of registrant as specified in its charter) Delaware 04-3402944 (State or other juri ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q (Mark One) ☒QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2019 OR ☐TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from N/A to . Commission file number 0-23695 BROOKLINE BANCORP INC. (Exact name of registrant as specified in its charter) Delaware 04-3402944 (State or other jurisdict ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2019 Commission file number 0-23695 Brookline Bancorp, Inc. (Exact name of registrant as specified in its charter) Delaware 04-3402944 (State or other jurisdiction of incorporation or organization) (I.R.S. Employer Identification No.) 131 Clarendon Street, Boston, MA 02116 (Address of principal executi ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-K x ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934, for the Fiscal Year Ended December 31, 2018, or o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934, for the transition period from N/A to . Commission File Number: 0-23695 BROOKLINE BANCORP, INC. (Exact name of registrant as specified in its charter) Delaware (State or other jurisdiction of incorporatio ...