Editor-in-chief Murat Sabuncu, cartoonist Musa Kart and other staff were detained for questioning earlier this week - some following raids at their homes - for allegedly supporting Kurdish militants as well as a movement led by Fethullah Gulen, the US-based businessman whom Turkey accuses of masterminding the failed coup in July.
The court ruled for their formal arrests on Saturday, the Associated Press reported.
Their detentions came amid a widening government crackdown on opposition voices. On Friday, authorities arrested the two co-chairs of Turkey's pro-Kurdish political party and several other party lawmakers for alleged ties to Kurdish militants.
Turkey's Western allies have voiced concern over the clampdown on Cumhuriyet and the pro-Kurdish party.