New York's 3rd State Senate district is one of 63 districts of the New York State Senate.

It has been represented by Republican L. Dean Murray since 2023.

District 3 covers much of south-central Suffolk County on Long Island, including portions of Brookhaven and Islip.

Most of Brentwood, the largest census-designated place on Long Island, is located within the district.

[4] The district overlaps with New York's 1st and 2nd congressional districts, and with the 1st, 2nd, 3rd, 5th, 6th, 7th, and 8th districts of the New York State Assembly.