Rhododendron williamsianum Rehder & E. H. Wilson 1913, is a plant with important horticultural value. Here we report its chloroplast genome. The total length of the chloroplast genome was 205,424 bp, with a GC content of 35.8%. It consisted of a 107,968 bp large single copy, a 2606 bp small single copy, and a pair of 47,425 bp inverted repeats separating them. Within the chloroplast genome, there were a total of 110 unique genes, which included 76 protein-coding genes, 4 rRNA genes, and 30 tRNA genes. Our phylogenetic analyses indicated that R. williamsianum was closely genetically related to R. sutchuenense and R. jingangshanicum . The findings from this study not only contribute to the genetic database of Rhododendron plants but also have implications for evolutionary research within the family Ericaceae.