Across the world, Кястутис (Kestutis 
, Kęstutis 
, Кястутис 
) is quite a rare boy's given name. The first name Кястутис is characteristic of Lithuania, where it is a common male name, Ireland, where it is quite a rare boy's name, and Albania, where it is a rare boy's name. Measured by absolute frequency, it is the most numerous in Lithuania, the United Kingdom, and the United States. Much less frequently, Кястутис is the last name as well as the forename.
| VARIANT | COUNTRY |
|---|---|
| Kestutis | Lithuania, Afghanistan, United States, Ireland, United Kingdom |
| Kęstutis | Lithuania, United States, Germany, United Kingdom, Norway |
| Кястутис | Belarus, Lithuania, Russia, Ukraine |
| Kyastutis | Russia |
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каунас, кястутис Lithuanian chess player, LT (b. 1942) |
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настопка, кястутис Lithuanian academic, LT (b. 1945) |
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кястутис главяцкас Lithuanian politician (1949-2021), LT (b. 1949) |
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кястутис даукшис Lithuanian politician, LT (b. 1960) |
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кястутис навицкас Lithuanian politician, LT (b. 1970) |
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кемзура, кястутис Lithuanian basketball player, LT (b. 1970) |
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| латожа, кястутис Lithuanian footballer, LT (b. 1950) |
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| рузгис, кястутис броневич Lithuanian footballer, LT (b. 1962) |
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| кяблис, кястутис Lithuanian rower, LT (b. 1976) |
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| марчюлёнис, кястутис Lithuanian basketball player, LT (b. 1977) |
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Вянгалис, Чяснавичюс, Зокайтис, Клебавичюс, Андряяускас, Ашмантас, Григайтис, Даубарис, Кундротас, Милькинтис, Монтвила, Пятрайтис, Слесорайтис, Бержинскас, and Симонайтис