Streptococcus pneumoniae is a normal flora in the upper respiratory tract but can cause Acute Respiratory Tract Infection (ARI), peritonitis, sepsis and meningitis. The widespread use of inappropriate antibiotics to treat Streptococcus pneumoniae infection causes antibiotic resistance. Meanwhile, Streptococcus pneumonia requires iron in its growth, namely as a cofactor for the ribonucleotide reductase enzyme, which plays a vital role in DNA synthesis. This study aimed to determine the antimicrobial activity of sappan wood extract (SWE) against Streptococcus pneumonia and the role of SWE as iron chelators on antimicrobial activity. The study was conducted by establishing a minimum inhibitory concentration (MIC) and a minimum bactericidal concentration (MBC) against Streptococcus pneumoniae and is evaluated using Total Plate Count (TPC), the diameter of the inhibitory zone and the measurement of iron levels using Atomic Absorption S. pectrophotometer. The results showed that the MIC values for Streptococcus pneumonia 103 and 105 CFU/mL were 32 ppm and 64 ppm, respectively, with the MIC values of 64 ppm and 128 ppm, respectively.