| Consort: | yes |
| Hedwig Sophia of Brandenburg | |
| Succession: | Landgravine consort of Hesse-Kassel |
| Reign: | 1649 – 16 July 1663 |
| Issue: | Charlotte Amelie, Queen of Denmark William VII, Landgrave of Hesse-Kassel Luise Charles I, Landgrave of Hesse-Kassel Philip, Landgrave of Hesse-Philippsthal Georg Elisabeth Henriëtte, Electoral Princess of Brandenburg |
| House: | Hohenzollern |
| Father: | George William, Elector of Brandenburg |
| Mother: | Elizabeth Charlotte of the Palatinate |
| Birth Date: | 14 July 1623 |
| Birth Place: | Berlin |
| Death Date: | 26 June 1683 (aged 59) |
| Death Place: | Schmalkalden |
Hedwig Sophia of Brandenburg (14 July 1623, Berlin – 26 June 1683, Schmalkalden) was Landgravine consort of Hesse-Kassel by marriage to William VI, Landgrave of Hesse-Kassel, and regent from 1663 until 1677 during the minority of her sons, William VII, Landgrave of Hesse-Kassel and Charles I, Landgrave of Hesse-Kassel.
She was the daughter of George William, Elector of Brandenburg and Elizabeth Charlotte of the Palatinate. She married William VI, Landgrave of Hesse-Kassel in 1649.
Upon the death of her spouse in 1663, he was succeeded by their son, William VII, Landgrave of Hesse-Kassel. As his mother and guardian, she became regent. Her regency was terminated upon the death of her son in 1670, but as he was succeeded by her second son, Charles I, Landgrave of Hesse-Kassel, who was also a minor, she was confirmed as such again.
During her regency, she repaired the finances of the state, which had been drained during the Thirty Years' War, by raised taxes. She kept the peace despite French expansionism until 1673, when she allied with her brother in Brandenburg against France.
During her last years as regent, she delayed her mandate to the dislike of her son until she was forced to hand over the regency in 1677.
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