plead / pleaded / pled
The past forms of plead.
Pleaded is the past tense and past participle of plead: She pleaded guilty. She has pleaded guilty. Use pleaded.
Examples
Use The defendant pleaded not guilty. (past tense of plead)
Avoid The defendant pled not guilty. (a variant of pleaded)
Dictionaries list pled as a variant, and it is common in American legal writing. However, many people still consider pled an error and judge the speaker who uses it.