Holger Henry Nielsen (2 October 1910 – 18 November 1969) was a Danish middle- and long-distance runner.

Nielsen held the 3000 m world record from 1934 to 1936 and placed third in men's 10,000 metres at the 1934 European Championships.

Early in his career Nielsen trained in Finland, which was the leading distance-running country at the time, and learned from Finnish runners.

[4][6] Later that year, Nielsen won bronze in the 10,000 m at the inaugural European Championships in Turin, losing only to Finland's Ilmari Salminen and Arvo Askola; he was Denmark's only medalist in the meet.

[5] His world record was broken by Finland's Gunnar Höckert, who ran 8:14.8 in September 1936.