Zurich, Switzerland (BBN)-Nepal Football Association president and ex-Asian football vice-president Thapa, 55, was found guilty of "various acts of misconduct over several years".
He is also under investigation by Nepalese authorities for allegedly embezzling millions of pounds of football development money, reports BBC.
Lao Football Federation chief Viphet Sihachakr was given a two-year ban.
Fifa said Sihachakr "solicited and accepted a payment from another football official" in relation to the 2011 elections for the Fifa executive committee at the Asian Football Confederation congress.
Thapa, in the context of the 2009 and 2011 elections at the Asian Football Confederation congress, was accused by Fifa of "committing various acts of misconduct ...including the solicitation and acceptance of cash payments from another football official, for both personal and family gain".
He told the BBC he would fight against the decision.
"I had been extending co-operation to their investigation for the last four years. I will now appeal it at the Court of Arbitration for Sport," said Thapa, who is also a minister of the Nepal parliament.
BBN/SK/AD