England-born Reo-Coker, who has Sierra Leonean roots, was a target of Leone Stars coach Christian Cole.
Sky Sports revealed earlier this week that the Villa man would not be accepting a call-up from the West African side and the 26-year-old has confirmed he contacted the Sierra Leone FA informing them he would like to retain the option of playing for England.
"I'm flattered by the invitation to play for Sierra Leone and I want to thank the SLFA as I consider it as a mark of respect," said Reo-Coker.
"But I can't play for Sierra Leone because at the moment my concentration is to win a regular place in my club Aston Villa.
"Besides, I believe I still have the prospect to play for England as I'm still young to fight for a place."
Reo-Coker captained England at Under-21 level but is yet to feature for the senior side, meaning he is eligible to play for the Leone Stars under Fifa's national regulations.
Nahim Khadi, the president of the SFLA, was naturally disappointed with the midfielder's decision to turn down the offer.
"I'm disappointed with Reo-Coker's decision because I was convinced that he would accept our invitations," said Khadi.
"I think he knows what's best for him and he believes the decision he has taken is his own best interest."
Reo-Coker is the second English footballer of Sierra Leona descent to have spurned an offer to play for the West African nation in recent months.
Barnet striker Steve Kabba, a former Crystal Palace and Sheffield United man, also rejected an invitation to join the Leone Stars.