<P>Farnesol, a quorum‐sensing molecule, was used successfully to improve laccase production in submerged cultures of <I>Trametes versicolor</I>. At the optimal farnesol concentration of 60 μM added at the beginning of the culture, the extracellular laccase activity reached 629.3 U L<SUP>−1</SUP> after 6 days of cultivation, which represented a 1.92‐fold increase relative to the control without farnesol treatment. The addition of farnesol resulted in an increase in the accumulation of H<SUB>2</SUB>O<SUB>2</SUB> and an increased expression of the laccase (<I>lac</I>) gene and the <I>RhoA</I> gene. The <I>RhoA</I> gene correlated with hyperbranched mycelia, which facilitated the secretion of the intracellular laccase. This study provides a basis for understanding the induction mechanism of farnesol for enhancing laccase production.</P>