Leuchtturm Bremerhaven Unterfeuer, Navigation lighthouse in Mitte district, Bremerhaven, Germany.

The Unterfeuer Bremerhaven is a round tower built in 1893 from a steel skeleton clad with steel plates, standing 26 metres tall on the Willy-Brandt-Platz next to the Zoo am Meer. Its light sits 21 metres above mean high water in the upper white section. It forms the lower light of the Bremerhaven leading line, paired with the Oberfeuer about 200 metres north.

The tower was built in 1893 to plans by harbour construction director Rudolf Rudloff on the south mole of the lock to the Neuer Hafen, as a steel skeleton clad in steel plates. It first burned petroleum, then gas, and has used an electric spotlight since 1925; operation was automated in 1942. In 1992 the tower was moved 56 metres to the Seebäderkaje and raised to 26 metres so ships would no longer block its light. It has been a listed monument since 1978.

Because of its bulbous dome and slender shaft, people in Bremerhaven nicknamed the tower "Minarett" (minaret) or "Zwiebelturm" (onion tower). The tower appears on a 70-cent Deutsche Post stamp from the "Leuchttürme" series, designed by Johannes Graf of Dortmund and issued on 8 June 2017.

The tower stands on the Willy-Brandt-Platz waterfront next to the Zoo am Meer, about 200 metres south of the Oberfeuer, so both lights of the leading line can be seen from the same spot. It is reached on foot along the Seebäderkaje; the light itself is automatic and not open to visitors.

The tower was originally 22.40 meters tall and stood on the south mole of the lock to the Neuer Hafen. In 1992 it was moved 56 meters to the Seebäderkaje and raised to 26 meters so ships would no longer block its light. The lighthouse has been a protected monument since 1978.