The novel metallosurfactant Cu(II)-1-tetradecyldiethylenetriamine (Cu(II)TDET) was prepared, and the hydrolyses of 2-acetoxy-5-nitrobenzoic acid (1), 4-acetoxy-3-nitrobenzoic acid (2), 4-nitrophenyl acetate (3), and 2-nitrophenyl acetate (4) in the presence of micellar Cu(II)TDET were examined. The rate of ester hydrolysis for the series followed the order 1 approximate to 2 > 3 > 4. The larger observed rate (k(psi)) for 1 and 2 was attributed to (i) electrostatic interaction between the carboxylate anion and the cationic metallomicelle surface and (ii) the formation of a ternary complex metal:surfactant ligand:substrate (MLnS). The position of the carboxylate anion in the substrate did not significantly affect catalysis. Similar rates were observed when the carboxylate anion was ortho to the acyl ester 1 or para to the reaction center 2. The absence of a significant difference may be associated with the ternary complex coordination geometry, which unfavorably aligned the ligated substrate and the metal-bound hydroxyl. Mixed micellar solutions containing Cu(II)TDET and MTAB or Triton X-100 were examined. Added cosurfactants have a pronounced effect on the catalytic activity of Cu(II)TDET. At a low concentration of Cu(II)TDET the addition of MTAB or Triton X-100 increased the pseudo-first-order rate constant (k(psi)) for the hydrolysis of 1 and 3 relative to the rate in pure Cu(II)TDET. The addition of a cosurfactant increased the total micellar volume (V-M), promoting substrate incorporation within the pseudophase. At higher metallosurfactant concentration, the rate enhancement was smaller due to the dilution of the substrate within the co-micellar pseudophase.