Taxonomical analyses were performed on strain CPA58T, a novel isolate obtained from surface-sterilized aboveground tissues of the halophyte Halimione portulacoides, collected from a salt marsh in Ria de Aveiro, Portugal. The strain was Gram-stain-negative, rod-shaped, oxidase-negative and catalase-positive. Optimal growth was observed at 26 °C, at pH 6-8 and in the presence of 2 to 3 % (w/v) NaCl. Phylogenetic analyses, based on the 16S rRNA gene sequence, showed that strain CPA58T belongs to the genus Zunongwangia, with highest sequence similarities to both Zunongwangia profunda SM-A87T and Zunongwangia mangrovi P2E16T (96.5 %), followed by Zunongwangia atlantica 22II14-10F7T (95.9 %). The principal fatty acids were iso-C15 : 0, summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH) and iso-C17 : 0 3-OH. The major respiratory quinone was MK-6 and the DNA G+C content was 35.1 mol%. Phylogenetic and chemotaxonomic analyses clearly placed strain CPA58T in the genus Zunongwangia. However, 16S rRNA gene sequence analysis showed that the threshold for same species relatedness was not surpassed, and biochemical tests revealed diagnostic characteristics that differentiated this strain from other type strains of species of the genus Zunongwangia. Overall, the analyses showed that strain CPA58T represents a novel species within the genus Zunongwangia, for which the name Zunongwangia endophytica sp. nov. is proposed, with the type strain CPA58T (=CECT 9128T=LMG 29517T).