The naira depreciated against the dollar at the parallel market on Friday, closing the week at N225.5.
The naira lost N0.5 as it exchanged for N225.5 against the dollar, slightly less than its previous value of N225, according to NAN.
Meanwhile, it exchanged at N197 to the dollar at the interbank window.
Traders at the market said the demand for dollar had been on the increase as businessmen and travelers bought it for various reasons.
The last time the naira closed firm on the last day of the week was September 19, when it firmed by one point against the dollar.
President Muhammadu Buhari has ruled out the possibility of further devaluing the Nigerian currency.