Firma Y - Porsgrunn
- Ymis AS
- Yildirim
- Yara Porsgrunn ASA
- Ytredal Invest AS
- Yeshan Getie
- Yemsrach Mintesnot
- Yt Bemanning AS
- Ynkova Hristiana
- Yelizaveta Sudavykova
- Yeah Kvist
- Yevhenii Barakaskyh
- Yevhen Otradnykh
- Yuliia Potapchuk
- Yuliia Plokhotniuk
- Yuliia Yuryna
- Yerheniia Yelfimova
- Yehor Klymok
- Yuliia Mirochnyk
- Yurii Potapchuk
- Yehov Vorobiov
- Yullia Plokhutniuk
- Yuliia Douhalink
- Yelyzaveta Varvarych
- Yuliia Hrykhno
- Yacht Tech AS
- Yx Eidanger
- Yoga Boda
- Ymse Design Osen
- Yggdrasil Møbelsnekker Lunde
- Yrkestrafikkforbundet Avd 15 nedre Telemark
- Yven Hy Consult Henning
- Yara Norge AS Avd Hydrovegen Porsgrunn
- Yogaspiren Marianne Synnes Kaasa
- Yoga med Marianne Rognlien Røine
- Yoga nord Maria Julie Tollefsen
- Ytredal Engineering Per Olav Ytredal