The Raman spectra of liquid 3-fluorostyrene show pairs of bands whose temperature-dependent intensities clearly suggest the occurrence of a conformational equilibrium. From these bands, assigned to cis and trans conformers, a trans–cis energy difference of 0.70 ± 0.20 kJ mol−1 was obtained for the liquid phase, higher than the reported gas-phase microwave and ab initio values. The effects of dilution with several solvents of different polarity properties are reported and the improved relative stability of the cis form in high-polarity solvents is interpreted in terms of medium effects on intramolecular through-space dipole–dipole interactions.