Carl "Carlo" Otto David von Dardel (26 October 1880 – 29 November 1955) was a Swedish diplomat. After completing legal studies at Uppsala University, he entered the Swedish diplomatic service in 1907 as an attaché in Vienna, later serving in Brussels, Narvik, Bern, London, Montreal, and Chicago. In Brussels, he represented Sweden at international conferences in 1909 and 1910. von Dardel was appointed consul general in Batavia (1930–1933), where he promoted Swedish governmental and commercial interests in the Dutch East Indies, and later served as consul general in Sydney (1933–1945), with jurisdiction over the Fiji Islands, until his retirement.
von Dardel began his diplomatic career when he was appointed attaché in Vienna on 7 August 1907, before being transferred to Brussels in the same capacity on 7 October 1908. While stationed in Brussels, he represented Sweden as a delegate to the 1909 Conference on the Importation of Arms into Africa and the 1910 World Congress of International Associations.
On 30 December 1910, von Dardel was appointed second secretary at the Swedish Ministry for Foreign Affairs, marking the beginning of a succession of increasingly senior diplomatic postings. He served as acting consul in Narvik from 11 April 1913 and became vice consul there on 31 December 1913. During the First World War, he was appointed acting legation secretary in Bern on 17 August 1915, followed by the same position in London on 19 May 1917. He was subsequently named acting consul general in Montreal on 30 August 1918, and consul in Chicago on 17 June 1921.
As Swedish consul in Chicago, von Dardel viewed his role as extending beyond traditional consular duties. He became an important cultural bridge between Sweden and the hundreds of thousands of Swedish Americans living in the American Midwest. In close cooperation with the Augustana Synod, he promoted exchanges of clergy and established scholarship programs designed to strengthen connections with Sweden and foster greater awareness of modern Swedish society among the emigrant community.
From 1930 to 1933, von Dardel served as consul general in Batavia, the capital of the Dutch East Indies. As head of the Swedish consulate general, he represented both the Swedish state and Swedish commercial interests throughout the region. His responsibilities included promoting Swedish exports, monitoring economic developments, and supporting Swedish companies active in the Javanese market, including AB Separator, ASEA, LM Ericsson, SKF, and Svenska Tändsticks AB.
On 7 July 1933, the Foreign Office approved his appointment as consul general in Sydney, with jurisdiction over the Fiji Islands. He remained in Sydney until 1945 when he retired.
von Dardel died on 29 November 1955 at Falun Hospital in Falun, Sweden. A memorial service was held at Leksand Chapel in Leksand on 4 December 1955, after which he was interred at Leksand Cemetery.
