The Meaning of IYKYK: What It Is and How To Use It

Do you know what the internet slang IYKYK means? This guide will provide you with all of the needed information on the acronym IYKYK, including its definition, usage, example sentences, and more!

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What does the abbreviation IYKYK mean?

According to Hashtag Dictionary and Style Blueprint, the social media acronym IYKYK stands for “if you know you know.” Daily Dot states that this hashtag or phrase is often used to denote an inside joke, hidden gem, or exclusive piece of information that only a few people will understand. It is often used as a hashtag on different social media sites like Snapchat, Tiktok, Instagram and Twitter. TikTokers will use this hashtag in the body of their post, while Twitter users might attach the hashtag to retweets. 

The hashtag IYKYK is also used in a great number of memes on websites like Twitter. People – particularly of the millennial generation – use the trending phrase everywhere to refer to different pop culture references or inside jokes between friends or classmates. The most popular Urban Dictionary post for IYKYK was published in 2016, and confirms the definition “if you know you know.”

Is the abbreviation IYKYK casual or formal?

IYKYK is an extremely casual piece of lingo and should be reserved exclusively for casual settings. Slang terms like IYKYK are not appropriate to use in professional or formal circumstances like business negotiations, letters, or professional emails. Below is an example of a situation in which it would be very inappropriate to use the phrase IYKYK, followed by a revised version of the same message.

In the below example, Stef is an employee at a small company. She is very close with her coworkers and they have many inside jokes together. One day, Stef’s boss Lara overheard these inside jokes and emailed Stef about it because it sounded like one of the jokes was at the expense of another one of the employees at the company. Stef replies to her boss.


OMG Lara no that is not what we meant at all! Lou is totally 100% in on the joke, he’s the one who made it in the first place, it’s sort of an IYKYK thing I guess LOL. We love Lou and we’d never say anything to hurt him, I promise it’s all in good fun.


Hi Lara,

First of all, I want to offer my profuse apology at the way our joke came off to you. I can assure you, Lou is completely in on the joke – he is the one who made it in the first place and he has reassured us that he thinks the joke is funny. Regardless, I will advise the rest of the group that we should think more carefully before sharing inside jokes like this at work as our goal is never to offend anybody. Thank you for bringing this to our attention, and again, my apologies.



Here, Stef should be sure to maintain proper email etiquette and professional dialogue when communicating with her boss. Chat speak and slang words are always inappropriate in business emails, but particularly in ones that may lead to disciplinary action if handled incorrectly.

What are other abbreviations like IYKYK?

Slang It lists many similar phrases to the abbreviation IYKYK. All of these are considered casual slang abbreviations that can be used on social media or in text messaging.

  • LYK – Let You Know
  • LMK – Let Me KNow
  • IK – I Know
  • DYK – Do You Know
  • YKI – You Know It
  • JLYK – Just Letting You Know

How can IYKYK be used in a sentence?

The trending phrase IYKYK can be used in a variety of different ways both on social media or in text messaging. This can be used in a caption or in a comment, and is usually seen as a hashtag.

In this first example, we see a comment section on Janel’s Instagram post, in which she posted a pic from last night’s party. She talks with her friend Sara in the comment section.

Sara: OMG looks like you’re at it again you crazy #IYKYK

Janel: OMG LOL, don’t bring that up! My grandmother follows me here haha.

Sara: LOL, well I have copious amounts of FOMO so I will do what I want!

Janel: It’s not my fault u have the flu! Heal up soon and I promise we will be back at it ASAP.

Sara: I hope so. The club is so much more fun than my bed… especially when I’ve been sitting in it for two weeks.

Janel: Miss u! X O X O

Here, Sara uses IYKYK to refer to something that is clearly an inside joke between her and Janel. This is not something appropriate that Janel wants her to bring up because she is scared of her family finding out about the inside joke. In this next example, Janel’s mother questions her about one of her Instagram captions.

Mom: Janel, what is this?

Janel: What is what?

Mom: This caption: You can take the cow out of boy, but you can’t take the boy out of cow. #IYKYK. What is ick-yick?

Janel: It’s not ‘ick-yick.’ It’s ‘if you know you know.’ It was just something silly that Megan said when we went to square dancing night at that place downtown. An inside joke. Since I was wearing those cowboy boots.

Overall, the abbreviation IYKYK stands for “if you know you know.” This phrase is often used as a hashtag that refers to an inside joke, hidden gem, or piece of exclusive information. This is a very common piece of slang that is used frequently in captions or comments on social media as well as in text messaging.