Bernard Johannes "Joost" Eerdmans (born 9 January 1971) is a Dutch politician, broadcaster and former civil servant who has served as Leader of JA21 since 18 December 2020, a party he co-founded with Annabel Nanninga.

Together with then PvdA MP Aleid Wolfsen, he submitted a bill to punish animal cruelty more severely and argued for increasing minimum sentencing for violent crimes.

For the 2006 general election, Eerdmans split with the LPF to form a new political party called One NL with Marco Pastors of Leefbaar Rotterdam.

After the dismal result of One NL in the 2006 election, Eerdmans left Dutch politics and worked in business before forging a career as a television and radio broadcaster.

For the 2021 general election, Eerdmans announced a return to national politics and was to be fourth on the party list of FvD led by Thierry Baudet.

[6] After leaving the Forum for Democracy, Eerdmans founded a new political party JA21 (Right Answer 2021) with ex-FvD members which aimed to compete in the 2021 general election.

[7] He also stated that JA21 would function as a "right-wing no-nonsense party" of "common sense" that would appeal to Dutch voters who saw the VVD as having grown too left, the PVV as too right and the Forum for Democracy as having lost its course and that JA21 would stick to the "original points" of the FvD.

[9] The House later adopted another motion by Eerdmans in which he called on the government to revoke environment pressure group Extinction Rebellion's designation as a charitable organization.

[10] When the right-wing Schoof cabinet presented its 2025 budget that included €2 billion in education cuts, Eerdmans formed the self-named "unholy alliance" with other centrist and conservative opposition parties.