Hendrikus Albertus Lorentz (18 September 1871 – 2 September 1944) was a Dutch explorer in New Guinea and diplomat in South Africa.

He was born to Theodorus Apolonius Ninus Lorentz, a tobacco grower in East Java who had returned to the Netherlands and Marie Soet in 1871. Lorentz studied law and biology at Utrecht University and married Marie Louise Clemence baroness Van Zuylen van Nievelt.

Lorentz participated in three expeditions to Dutch New Guinea, the present-day Indonesian (western) portion of the island of New Guinea. The first was the North New Guinea Expedition in 1903, led by Arthur Wichmann. Lorentz himself led expeditions in 1907 and 1909–1910.

Places and species named after Lorentz

• Lorentz National Park and the Lorentz River (Undir or Unir in Indonesian) in southern New Guinea
• Lorentz catfish and Lorentz's mosaic-tailed rat
• The non-venomous Lorentz's tree snake Dendrelaphis lorentzii (Van Lidth de Jeude, 1911). The holotype was collected at Sabang on the Noordrivier (later renamed the Lorentz River) during Lorentz's third Papuan expedition.

Collector

Lorentz collected indigenous artifacts and bird samples. The latter he sent to the Rijksmuseum van Natuurlijke Historie at Leiden, The Netherlands. Some examples:

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  Flame bowerbird (Sericulus ardens) from Southern New Guinea in 1907. Original description Xanthomelus ardens, later subspecies Sericulus aureus ardens.
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  Breast view of the same sample. Flame bowerbird (Sericulus ardens).
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  Golden-backed whistler (Pachycephala aurea), New Guinea expedition 1909
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  Hooded pitohui (Pitohui dichrous), received 1909
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  Streak-headed honeyeater (Pycnopygius stictocephalus), New Guinea expedition 1909
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  Black thicket fantail (Rhipidura maculipectus), New Guinea expedition 1909
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  Broad-billed flycatcher (Myiagra ruficollis ruficollis), from Kupang, Timor, 1909