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. For the 2022 election, the 3rd district was redistricted from the old 4th district.
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.
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.