This article, part of the Corpus Ponderum Antiquorum et Islamicorum (= CPAI ) project, introduces 302 balance weights from the collection of the Ephesus Museum, located in Selçuk (Efes), İzmir. The majority of the weights are made of lead, with a smaller number made of bronze. Among these, 115 weights follow the Greek system, while 187 belong to the Roman system, of which some are classified as Byzantine weights. The find spots of these weights are primarily in and around Selçuk and nearby archaeological sites, providing important data for their provenance or attribution. Although some weights bear ethnics, most only feature unit marks; however, their find spots enable accurate attribution. The Roman system weights, especially the librae, range from the theoretical 12 unciae to as much as 25 unciae, indicating adjustments over time due to inflation and devaluation. Among the Byzantine weights, the glass ones, dating from the 5th to 7th centuries AD, are also notable for the monograms they bear. Additionally, a weight made from a coin dates to the 10th-11th centuries AD.