Seisyll Gruffydd

{{Infobox officeholder

| honorific_prefix   = 
| 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 }}