After first underscoring that peace operations (PO) are characterized by the fact that - very often - the troops contributing countries (TCC) and the international organizations (IO) involved tend to deny IHL applicability to their own action, this article addresses in more details three specific contexts. The UN forces in Democratic Republic of Congo context is quite emblematic because until 2006, the UN forces deployed were generally viewed as non-belligerent, thus entitled to protections granted by IHL to civilians. At the end of 2006 then again in 2007 and 2008, the UN forces took part in military against non-state organized armed groups, thus asking the question whether the UN forces should be considered as party to the NIAC in DRC. The "Unified Protector" operation in Libya allows the analysis of the applicability of IHL to TCC and IO under an IAC prism. Arguments have been put forward that TCC were not involved in an armed conflict nor did they carry out military operations whose objective was to submit/defeat the enemy. The African Union's implication in the NIAC in Somalia is interesting because it illustrates how the legitimate use of force in self-defence can turn peace forces into party to a NIAC.