Y mae Erthygl 13 Cytundeb y Cenhedloedd Unedig ar Hawliau’r Plentyn yn ymwneud â hawl plentyn i ryddid barn:

Mae gan blant yr hawl i gael a rhannu gwybodaeth onid yw’r wybodaeth yn niweidiol iddyn nhw ac i eraill.*

* Y mae’r testun hwn yn dod o fersiwn gryno o’r Cytundeb yn unig. Nid yw testun llawn y Cytundeb wedi’i gyfieithu i’r Gymraeg. Fodd bynnag, y mae cyfieithiad Saesneg yr erthygl hon fel a ganlyn:

"1. The child shall have the right to freedom of expression; this right shall include freedom to seek, receive and impart information and ideas of all kinds, regardless of frontiers, either orally, in writing or in print, in the form of art, or through any other media of the child's choice.

2. The exercise of this right may be subject to certain restrictions, but these shall only be such as are provided by law and are necessary:

(a) For respect of the rights or reputations of others; or

(b) For the protection of national security or of public order (ordre public), or of public health or morals."