"Häcken is a fantastic club that helps its talents. I feel it is the right place for me," says Omewa in a press release.
The contract runs until 2029.
"Her instinct for scoring goals is clear, and she is always looking for the next opportunity," says Häcken's football director Martin Ericsson.
Omewa most recently played for English side Nottingham Forest, and before that spent five and a half years in Denmark.
“I want to contribute with ‘joy’, just like my name,” says Omewa.
The 23-year-old recently made her debut for Nigeria's national team, and has been selected in the country's squad for the African Championships in Morocco next week.
Earlier in the summer, Häcken sold Swedish striker Felicia Schröder, which at the time became the most expensive transfer in the women's game ever.
