n-Dodecyl acrylate (DA) and dodecyl-4-vinyl benzoate (DVB) were copolymerized by conventional free-radical polymerization (CFRP); atom transfer radical polymerization (ATRP), and nitroxide-mediated living free-radical polymerization (NMLFRP) with benzoyl peroxide, 1-phenyl ethyl chloride/cuprous chloride/2,2'-bipyridine, and benzoyl peroxide/2,2,6,6-tetramethylpiperidinyl-1-oxy initiator systems, respectively. In CFRP and NMLFRP, toluene and xylene were used as solvents, whereas ATRP was performed in bulk. Mayo-Lewis, Kelen-Tudos, and Fineman-Ross methods were used for the determination of the monomer reactivity ratios (r(1) and r(2)). They all gave nearly the same values of r(1) and r(2) The reactivity ratios of the two monomers in CFRP, ATRP, and NMLFRP were 0.17 less than or equal to r(1) less than or equal to 0.4 (DA) and 1.0 less than or equal to r(2) less than or equal to 1.24 (DVB). The side-chain crystallinity of the copolymers decreased with an increasing DVB molar fraction.