National Suicide Hotline Improvement Act of 2017 (Sec. 3) This bill requires the Federal Communications Commission (FCC) to coordinate with the Substance Abuse and Mental Health Services Administration (SAMHSA) and the Department of Veterans Affairs (VA) to examine: (1) the feasibility of designating a three-digit dialing code for a national suicide prevention and mental health crisis hotline system; and (2) the effectiveness of the National Suicide Prevention Lifeline (1-800-273-TALK), including how well it addresses the needs of veterans. SAMHSA must report to the FCC: (1) the potential impact of a designated dialing code on suicide prevention, crisis services, and other suicide prevention and mental health crisis hotlines; and (2) recommendations for improving the National Suicide Prevention Lifeline. The VA must report to the FCC about how well the National Suicide Prevention Lifeline and the Veterans Crisis Line are working to address the needs of veterans. The FCC must report to Congress whether it recommends a dialing code, a cost-benefit analysis comparing the three-digit code to the current lifeline number, and cost estimates for service providers, states, and localities.