As some of the most commonly confused words in the English language, lay vs. lie (and determining which to use) present problems for English writers and speakers—even native ones. However, knowing whether to use lay or lie in a particular context requires knowing specific rules related to conjugating the verbs in present, past and past participle tenses. We'll review these rules here.
Lay vs. lie in present tense
The present tense rule related to lay vs. lie is the easiest to remember. Keep in mind that in this article, we are referring to "lie" in its meaning "to recline" rather than "untruth".
Lay requires an object while lie does not.
For example, you can lay a blanket over someone, because the object (blanket) is receiving the action of the verb. However, when you lie down, there is no object, so "lie" is the correct choice.
Remember that Bob Dylan song, "Lay Lady Lay"? Well, Dylan—although a great songwriter—used the verb incorrectly in his song. And then people wonder why English language rules are so difficult to remember!
The correct way, then, to sing that song would be "lie Lady lie, lie across my big brass bed." However, we'll trust that Dylan had his reasons for conjugating the verb incorrectly in his hit track.
Lay vs. lie in past tense
Here is where the grammar rules get really tricky with this particular pair of words—in the past tense. Why? Because the past tense of "lie" is "lay". What this means is that if you are supposed to use "lie" in the present tense—for example, "I need to go lie down"—you'll have to change that to "lay" if speaking past tense.
Consider this example: "Yesterday, the cat lay in the window sill all day long."
Sounds incorrect, doesn't it?
That's because most people get it wrong. If you're like most, your first inclination would be to use "laid" as the past tense verb form here, but that would be incorrect. "Laid" is the past tense of "lay," so you would only use that if "lay" is the correct verb form to use in present tense.
Here's an example: "I laid the paper down on the table, but someone lost it."
Lay vs. lie in past participle tense
Now, let's look at the past participle of both verb forms, starting with "lie". The past participle of "lie" is "lain".
Consider this example: "I have lain in bed all day and haven't accomplished anything."
So, if "lay" is the correct form of the verb in present tense (meaning there is an object that is placed down), the past participle tense is "laid" (which is the same as the past tense, so at least something about this is easy!)
Here's an example: "She has laid her purse somewhere and forgotten where."