Seisyll Gruffydd
{{Infobox officeholder
| name = Seisyll ap Morgan ap Ieuan | image = Seisyll ap Morgan ap Ieuan.png | image_size = | image_upright = | alt = | caption = Arlywydd Seisyll ap Morgan ap Ieuan addressing a meeting of the Kilikas-Boreal Cooperative Zone | order = | office = Arlywydd of Caergwynn | term_start = March 12, 2023 | predecessor = Rhys ap Ieuan ap Dafydd | successor = | office2 = Chancellor of the Department of Foreign Affairs | term_start2 = June 5, 2016 | term_end2 = March 12, 2023 | predecessor2 = Angharad Jones | successor2 = Martyn Glynn | birth_name = Seisyll Gruffydd
| birth_date = April 5, 1958 (age 66) | birth_place = Llandewi, Caergwynn | nationality = [[Caeric] | alma_mater = Prifysgol Morlais
| occupation =
- Diplomat
- Politician
| spouse = Catrin Carews | spouse =none | Religion = Association of Free Churches of Caergwynn }}