Bioassay-guided fractionation of a collection of Moorea bouillonii from Papua New Guinea led to the isolation of a new alkyl amide, mooreamide A (1), along with the cytotoxic apratoxins A–C and E. The planar structure of 1 was elucidated by NMR spectroscopy and mass spectrometry analysis. Structural homology between mooreamide A and the endogenous cannabinoid ligands, anandamide, and 2-arachidonoyl glycerol inspired its evaluation against the neuroreceptors CB1 and CB2. Mooreamide A was found to possess relatively potent and selective ligand binding activity to CB1 (K 1 = 0.47 µM) versus CB2 (K 1 > 25 µM). This represents the most potent marine-derived CB1 ligand described to date and adds to the growing family of marine metabolites that exhibit cannabinomimetic activity.