Extraction of Am3+ was done using a both-side diglycolamide-functionalised calixarene with eight DGA pendent arms (Calix8DGA) in several organic diluents. The observed extraction trend was nitrobenzene>n-dodecane (with 5% isodecanol as phase modifier) > phenyltrifluoromethylsulphone (PTMS) > hexone∼2-nitrophenyloctylether∼1-octanol>chloroform at 0.1 M HNO3, which changed at higher acidities (3 M) showing crossovers between the nitrobenzene–n-dodecane and the PTMS–hexone pairs. The Am3+ extraction as a function of the nitric acid concentration showed increasing D values with increasing acidities. The extraction behaviour was correlated with various parameters such as Schmidt's diluent parameter, dielectric constant and so on. The nature of the extracted species was ascertained in various diluents by the slope analysis method, while temperature variation studies were carried out to determine the thermodynamic parameters, which in turn explain the extraction mechanism. The separation behaviour of Am3+ with respect to UO22+ and Sr2+ was also investigated in these diluents.