Pineapple (Ananas comosus (L.) Merr.) is the third-most important tropical fruit traded and widely cultivated in Indonesia with various cultivars. This study identifies genetic diversity and determines the phenetic relationship of nine pineapple accessions based on inter-simple sequence repeat (ISSR) markers. Four ISSR primers were utilized for genetic diversity analysis and diversity relationships using POPGENE 1.31 and MVSP 3.2 to form a dendrogram. The results showed that nine pineapple accessions revealed the successful amplification of 50 DNA bands, 46 polymorphic, with a percentage average of 89.38%. The calculation result of the effective alleles (Ne), Nei’s gene diversity (h), Shannon information index (I), and polymorphism information content (PIC) showed that ISSR 1 had the highest value and ISSR 16 had the lowest value. The average of the Ne value was 1.44; the average of h was 0.28, which indicated low genetic variation; the average of (I) was 0.43, which indicated that not all groups had the same frequency; the averages of the PIC value of 0.28 which showed that the four ISSR primers used were somewhat informative. The results of the phenetic relationship based on ISSR molecular markers showed two clusters that separated the accession of ‘Spanish’ from the accession of ‘Queen’ and ‘Cayenne.’ This resulting study showed that ISSR analysis was suitable for studying genetic diversity among pineapple cultivars.