Gas‐phase solvation of halides by 1,3‐butadiene has been studied via a combination of photoelectron spectroscopy and density functional theory. Photoelectron spectra for X−⋯(C4H6)n (X=Cl, Br, I where n=1‐3, 1–3 and 1–7 respectively) are presented. For all complexes, the calculated structures indicate that butadiene is bound in a bidentate fashion through hydrogen‐bonding, with the chloride complex showing the greatest degree of stabilisation of the internal C−C rotation of cis‐butadiene. In both Cl− and Br− complexes, the first solvation shell is shown to be at least
n=4
${n = 4}$
from the vertical detachment energies (VDEs), however for I−, increases in the VDE may suggest a metastable, partially filled, first solvation shell for
n=4
${n = 4}$
and a complete shell at
n=6
${n = 6}$
. These results have implications for gas‐phase clustering in atmospheric and extraterrestrial environments.