Atomistic molecular dynamics simulations have been used, apparently for the first time, to investigate self-assembly and organization of β-alkylated oligothiophenes adsorbed on graphite. We demonstrate that side-chain substitution is an effective means for the modification of molecular conformation and surface morphology.Comparisons between the unsubstituted tetrathiopene (4T) deposited on graphite and the β-alkylatedoligothiophenes demonstrate that the presence of long hydrocarbon side chains in 4T produces monolayerfilms with a higher degree of order at the molecular level. The results are in qualitative agreement withexperiments.