(This measure has not been amended since it was reported to the House on May 4, 2017. The summary of that version is repeated here.) Improving Support for Missing and Exploited Children Act of 2017 (Sec. 2) This bill amends the Missing Children's Assistance Act to revise the findings to, among other things, specify that the growing numbers of children who are victims of child sexual exploitation include victims of child sex trafficking and sextortion. (Sec. 3) The bill revises the definition of "missing child" to mean an individual under 18 years of age whose whereabouts are unknown to the individual's parent (currently, legal custodian). It specifies that a parent includes a legal guardian or an individual who functions as a parent (e.g., a grandparent). (Sec. 4) It revises existing functions and duties of the National Center on Missing and Exploited Children (NCMEC) and adds new requirements for the NCMEC, including to: provide training and technical assistance to help families, law enforcement agencies, and other entities respond to missing foster children and identify, locate, and recover child sex trafficking victims; provide forensic and direct on-site technical assistance, including facial reconstruction of skeletal remains, to help families, law enforcement agencies, and other entities identify deceased children; provide training, technical assistance, and information to help law enforcement agencies and nongovernmental organizations identify and locate non-compliant sex offenders; and develop and disseminate programs and information on sexting and sextortion to families, law enforcement agencies, and other entities. (Sec. 6) The NCMEC must make publicly available the annual report on missing children and the incidence of attempted child abductions.