楯齿龙目（Placodontia）又名盾齿龙目、齿龙目，意思为＂块状的牙齿＂，是群生存于三叠纪的海生爬行动物，在三叠纪-侏㑩纪灭绝事件中灭绝。一般认为牠们跟鳍龙超目有接近亲缘关系，而鳍龙类也包括蛇颈龙类。楯齿龙类身长通常为1到2公尺，最大型的物种可达3公尺。牠们拥有短而非常强壮的四肢。部分原始物种在外表上类似粗厚、水桶腰的蜥蜴，而其他的物种则因为背上的大型骨板，而类似乌龟。

在1830年发现第一个楯齿龙类的化石，楯齿龙类的化石目前已在欧洲、北非与中东发现。

Placodonts ("Tablet teeth") is an extinct order of marine reptiles that lived during the Triassic period, becoming extinct at the end of the period. It is believed that they were part of Sauropterygia, the group that includes plesiosaurs. Placodonts were generally between 1 to 2 m (3.3 to 6.6 ft) in length, with some of the largest measuring 3 m (9.8 ft) long.