Acyl carrier protein (ACP) plays a central role in many metabolic processes inside the cell, and almost 4% of the total enzymes inside the cell require it as a cofactor. Here, we report self-acylation properties in ACPs from Plasmodium falciparum and Brassica napus that are essential components of type II fatty acid biosynthesis (FAS II), disproving the existing notion that this phenomenon is restricted only to ACPs involved in polyketide biosynthesis. We also provide strong evidence to suggest that catalytic self-acylation is intrinsic to the individual ACP. Mutational analysis of these ACPs revealed the key residue(s) involved in this phenomenon. We also demonstrate that these FAS II ACPs exhibit a high degree of selectivity for self-acylation employing only dicarboxylic acids as substrates. A plausible mechanism for the self-acylation reaction is also proposed.