Background: Neuroendocrine neoplasms (NENs) are increasing in incidence globally. Previous analysis of the UK cancer database (National Cancer Registration and Analysis Service (NCRAS)) showed a notable female survival advantage in most tumour sites. This study aims to compare NCRAS to the Surveillance, Epidemiology, and End Results Program (SEER) to validate these results using the same statistical methods. Methods: A total of 14,834 and 108,399 patients with NENs were extracted from NCRAS and SEER, respectively. Sixty-months survival for both males and females for each anatomical site of NENs were calculated using restricted mean survival time (RMST) and Kaplan–Meier Survival estimates. The sixty-month RMST female survival advantage (FSA) was calculated. Results: FSA was similar in NCRAS and SEER. The highest FSA occurred in lung and stomach NENs. Conclusions: The data from SEER confirm the findings published by NCRAS. Female survival advantage remains unexplained.