Friendship is one of life’s greatest treasures, and English has plenty of idioms to celebrate it. From calling someone your “partner in crime” to saying you’re “joined at the hip,” these expressions capture the closeness and loyalty of true best friends.

Using friendship idioms adds warmth and personality to your conversations. They also help you sound more natural and expressive in English.

In this article, we’ll share 22 popular idioms for best friends, along with their meanings and examples.

1. Thick as Thieves

Meaning: Very close friends who share secrets.
Example: “Jake and Ryan are thick as thieves—they do everything together.”
Tone: Warm, affectionate.
Other ways to say it: Inseparable, like family.

2. Joined at the Hip

Meaning: Always together, inseparable.
Example: “Lisa and Emma are joined at the hip—they even have the same hobbies.”
Tone: Playful, affectionate.
Other ways to say it: Attached at the hip, inseparable duo.

3. A Shoulder to Cry On

Meaning: Someone who offers comfort and support.
Example: “Whenever I have a bad day, Sarah is always my shoulder to cry on.”
Tone: Supportive, emotional.
Other ways to say it: Rock, emotional support.

4. Through Thick and Thin

Meaning: Staying together no matter what happens.
Example: “We’ve been friends through thick and thin for over 20 years.”
Tone: Loyal, committed.
Other ways to say it: No matter what, always there.

5. Birds of a Feather

Meaning: Friends who are very similar.
Example: “Mia and I are birds of a feather—we love the same things.”
Tone: Playful, friendly.
Other ways to say it: Like-minded, cut from the same cloth.

6. Peas in a Pod

Meaning: Very similar in personality or interests.
Example: “Those two are like peas in a pod—they even finish each other’s sentences!”
Tone: Warm, affectionate.
Other ways to say it: Two of a kind, soulmates.

7. Two Peas in a Pod

Meaning: Nearly identical in personality or behavior.
Example: “They have the same laugh, same hobbies, and same jokes—they’re two peas in a pod!”
Tone: Lighthearted, friendly.
Other ways to say it: Mirror images, identical spirits.

8. Blood is Thicker than Water (But Not Always!)

Meaning: Friendships can be just as strong as family bonds.
Example: “My best friend is like my brother—proof that blood isn’t always thicker than water.”
Tone: Sentimental, affectionate.
Other ways to say it: Chosen family, lifelong bond.

9. My Ride or Die

Meaning: A friend who stays by your side no matter what.
Example: “Emma is my ride or die—I know she’ll always have my back.”
Tone: Loyal, emotional.
Other ways to say it: True companion, forever friend.

10. Like Two Sides of the Same Coin

Meaning: Different but complementing each other perfectly.
Example: “She’s loud, I’m quiet—but we’re like two sides of the same coin.”
Tone: Playful, affectionate.
Other ways to say it: Opposites attract, perfect balance.

11. Friend for Life

Meaning: A friendship that lasts forever.
Example: “We’ve been friends since childhood—she’s a friend for life.”
Tone: Warm, lasting.
Other ways to say it: Lifelong friend, forever bond.

12. A Friend in Need is a Friend Indeed

Meaning: True friends show up when you need them most.
Example: “When I was sick, he took care of me—that’s a friend in need.”
Tone: Appreciative, wise.
Other ways to say it: True friendship, dependable friend.

13. A Kindred Spirit

Meaning: Someone who deeply understands you.
Example: “We clicked instantly—she’s a kindred spirit.”
Tone: Warm, deep.
Other ways to say it: Soulmate, twin soul.

14. As Close as Family

Meaning: A best friend who feels like family.
Example: “We’ve known each other so long—we’re as close as family.”
Tone: Sentimental, loving.
Other ways to say it: Chosen family, like siblings.

15. Have Each Other’s Backs

Meaning: Always supporting each other.
Example: “No matter what happens, we always have each other’s backs.”
Tone: Trusting, loyal.
Other ways to say it: Always there, got your back.

16. Best Buds

Meaning: Best friends.
Example: “They’ve been best buds since high school.”
Tone: Friendly, casual.
Other ways to say it: Besties, BFFs.

17. Soul Sister/Brother

Meaning: A friend who connects with you on a deep level.
Example: “She’s not just my best friend—she’s my soul sister.”
Tone: Deep, affectionate.
Other ways to say it: Spiritual twin, soulmate.

18. My Right-Hand Person

Meaning: Someone you depend on.
Example: “I couldn’t get through life without my right-hand person.”
Tone: Trusting, dependable.
Other ways to say it: Go-to friend, trusted companion.

19. Cut from the Same Cloth

Meaning: Very similar in personality or values.
Example: “We have the same sense of humor—we’re cut from the same cloth.”
Tone: Complimentary, close.
Other ways to say it: Like-minded, similar souls.

20. Like Glue

Meaning: Sticking together no matter what.
Example: “We’ve been through so much, but we always stick together like glue.”
Tone: Loyal, affectionate.
Other ways to say it: Unbreakable bond, inseparable.

21. A Friend to the End

Meaning: A friendship that lasts forever.
Example: “No matter what happens, I know she’s a friend to the end.”
Tone: Warm, committed.
Other ways to say it: True friend, lifelong companion.

22. Brothers/Sisters from Another Mother

Meaning: A best friend who feels like family.
Example: “We’re not related, but he’s my brother from another mother.”
Tone: Playful, affectionate.
Other ways to say it: Chosen family, best friend forever.

Conclusion

Idioms for best friends show just how deep and special these bonds can be. Whether you describe someone as a “bosom buddy” or your “ride or die,” these 22 expressions make it easy to talk about close relationships with heart and flair.

Using them not only strengthens your English but also makes your speech feel more genuine and lively. Keep practicing these phrases to make your conversations about friendship even more meaningful. After all, a true friend—and the right words to describe them—are priceless.