"What Does Related-Party Transaction Mean?
A business deal or arrangement between two parties who are joined by a special relationship prior to the deal. For example, a business transaction between a major shareholder and the corporation, such as a contract for the shareholder's company to perform renovations to the corporation's offices, would be deemed a related-party transaction.
Investopedia Says
Investopedia explains Related-Party Transaction
American public companies are required to disclose all transactions with related parties such as executives, associates and their family members in their annual 10-K report. While the great majority of related-party transactions are perfectly normal, the special relationship inherent between the involved parties creates potential conflicts of interest which can result in actions which benefit the people involved as opposed to the shareholders. For example, in the infamous Enron scandal, related-party transactions with "special-purpose entities" were used to help the "
http://www.investopedia.com/terms/r/related-partytransaction...

"FocusIFRS - IAS 24 "Information relative aux parties liées ...
http://www.focusifrs.com/.../ias_24_information_relative_aux... - Cached
22 juil. 2010 – Une transaction entre parties liées est un transfert de ressources, de services ou d'obligations entre une entité présentant les états .."

related party transaction - opération entre parties liées (apparentées)

Je crois que votre traduction est tout à fait correcte. "Transaction entre parties liées: un transfert de ressources ou d'obligations entre des parties liées, sans tenir compte du fait qu'un prix soit facturé ou non." Je crois que le mot "transactions" doit être au pluriel dans votre cas.