Microduplication of chromosome 17p13.1 is a rarely reported chromosome abnormality associated with neurodevelopmental delays. We describe two unrelated patients with overlapping microduplications of chromosome 17p13.1. The first patient is a 2-year-old male who presented with neurodevelopmental delays and macrocephaly. He was found to have a de novo 788 kb copy gain of 17p13.2p13.1 and a de novo 134 kb copy gain of 17p13.1. These duplications include multiple candidate genes, including EFNB3, NLGN2, DLG4, GABARAP, and DULLARD, which may be responsible for neurodevelopmental delays in affected individuals. The second patient is a 29-year-old female with mild intellectual disability and relative macrocephaly. She was found to have a 62.5 kb copy gain of chromosome 17p13.1 that includes the DLG4, GABARAP, and DULLARD genes. The DLG4, GABARAP, and DULLARD genes included in the microduplications of both our patients appear to be candidate genes for neurodevelopmental delays and macrocephaly in individuals with 17p13.1 microduplication syndrome.