Ní Raghallaigh, who also works as a teacher, is taking annual leave to take part.
Kildare South Sinn Féin TD Shónagh Ní Raghallaigh has said that as an Irish Republican she knows "what it means to resist colonial violence and fight for dignity" as she prepares to join a protest flotilla bound for Gaza.
Ní Raghallaigh, who has also worked as a teacher, is taking annual leave to take part.
She said the mission is a "civilian effort to break the siege of Gaza".
Ní Raghallaigh compared the move to her own Republican background, saying she knows what it means to "fight for dignity".
She also declared that Republicanism is "about action" and that it is time to stand in "solidarity" and in "struggle".

Kfm Obituary Announcements (Saturday)
Sharp Rise In M9 Collisions With Garda Call-Outs Up Year-On-Year
Councillor Seeks Clarity On How Often Nightclubs and Late Bars In Naas Are Inspected For Fire Risks
Unpaid Eight-Month Work And Training Placement For Adults With Disabilities Branded "Extremely Unfair"
Department Of Education Defends Kildare SNA Cuts Amid Claims Of Reduced Need At Some Schools
Naas Nurses Threaten Escalation As Staffing Row Deepens
Driving Tests Face Disruption As RSA Testers To Strike Next Week