Puget Sound in Washington State (WA) has significant tidal energy resources, but the industry is at a nascent stage of development. At this stage, the availability of research and development (R&D) funding plays a critical role in the success or failure of renewable energy schemes. However, information about public interest in developing marine renewable energy technology, including tidal energy technology, in WA and the U.S. has been limited. Responses to a dichotomous choice referendum question on a mail survey sent to a representative sample of WA households were used to estimate residents' Willingness to Pay (WTP) for tidal energy R&D. Public preferences for policies to support tidal energy R&D were also assessed. WA households are WTP between $29M and $127M annually for tidal energy R&D, indicating public preference for an increase in government spending on tidal energy R&D over current levels. Public perceptions of potential social, environmental, and economic risks and benefits of developing tidal energy emerged as highly significant predictors of WTP.