Planktonic bacteria form biofilms, microbial aggregates embedded within matrix of extracellular polymeric substances (EPS) found on biotic and abiotic surfaces. Biofilms are responsible for oral diseases such dental caries, gingivitis, periodontal disease and are 10-1000 times more resistant to treatment. Fatty acids (FAs) have been used to control oral bacteria. This research aims to determine most active FAs preventing acid producing, acid tolerant S. mutans growth and biofilm formation. Minimum Inhibitory Concentration (MIC) of FAs was assessed by microdilution method using resazurin assay, followed by serial dilution and spot plating on BHI agar to establish the Minimum Bactericidal Concentration (MBC). Minimum Biofilm Inhibition Concentration (MBIC) was determined using crystal violet assay on developing S. mutans biofilms using BHI supplemented with 1% sucrose. Saturated MCFAs Octanoic, Decanoic and Undecanoic acid did not display antimicrobial or antibiofilm properties however, Lauric and Myristic acid displayed activity at high concentrations. LCFAs monounsaturated Oleic and polyunsaturated Linoleic acid displayed potent antimicrobial activity with MICs of 62.5 µM. Biofilm inhibition was 99.73% at 125 µM for Oleic and 100% at 65.5 µM for Linoleic compared to the negative control. Long chain polyunsaturated Omega-3 FAs α-Linoleic, Eicosapentaenoic Acid (EPA), Docosahexaenoic Acid (DHA) displayed strong activity with MIC’s ranging from 7.8 – 31.25 µg/ml. DHA is most promising antibiofilm agent with a MBIC at 15.625µg/ml. To conclude FAs structural orientation and chain length has an influence on antimicrobial and antibiofilm activity, with medium or long chain unsaturated FAs containing one or more double bonds appearing most potent.