75+ Best curiosity email subject lines

When used right, curiosity can be a powerful psychological trigger that helps improve the engagement rates for email campaigns.

You could use curiosity elements in the subject line to increase open rates or inject them inside the body to improve click-through & response rates. Either way, you can expect your campaigns to be vastly more effective with curiosity than without.

In this article, we’ve put together a bunch of ready-to-use curiosity email subject lines to inspire your marketing campaigns.

Best curiosity email subject lines

Curiosity-based subject lines are powerful because they draw the reader's attention and encourage them to open and read the email.

Here are some curiosity email subject lines to help you see how it is done:

5 Secrets ways to [Objective]

[Brand Name]: Your secret discount coupons

This is not cool [First Name]

Are we meeting tonight?

What happens in Vegas…

Quick question [First Name]

[Business Name]: Your surprise inside

Unlock special discounts (24 hrs only)

Dare to take up our challenge?

Your exclusive invitation awaits

How to become a VIP for free?

Got a question for you

Mind taking a look [First Name]?

Special savings for [First Name]

Black Friday special discount inside

This offer is valid till noon only!

Don't open this [First Name]

Your secret invitation [First Name]

[Brand Name]: Our special gift

Guess what you won [First Name]?

5 Dirty truths about [Topic]

What no one tells you about [Topic]

11 Hidden secrets about [Topic]

The hidden wonders of [Topic]

We kept our promise

Are we breaking up?

Curiosity subject lines

Because curiosity-based subject lines stand out in the inbox, they're more memorable than the usual emails, so your brand is more likely to be remembered as a result.

Here are some more curiosity subject lines for your reference:

Sneak peek at [Product Name]

Top secret fact about [Product Name]

3 Reasons you shouldn't buy [Product Name]

Here’s why you should love competition

7 Must-know facts about [Product Name]

[Brand Name]: Claim your surprise gift

Ready, [First Name]?

7 Mysteries surrounding [Topic]

[Product Name]: Your exclusive preview

[Product Name]: One thing to never forget

[Product Name]: 3 hidden high ROI features

How to get our VIP tier for 25% less

[Brand Name]: Enter our giveaway!

[Brand Name]: Announcing something new

Get ready for an exciting surprise!

Guess what's brewing?

Ready to be amazed? Here’s [Product Name]

Eyes here: [Product Name] launching soon

The cat is out of the bag, [First Name]

Brace yourself for the surprise, [First Name]

Guess what's on its way to you

Please accept this small gift

Your surprise discount revealed

Something amazing inside, [First Name]

How about a little surprise?

Good curiosity email subject line examples

Using curiosity in your subject lines will boost your open rates. It is important, however, to include a compelling offer in your copy to compel the reader to click through and make a purchase to make these opens worthwhile for you.

Let’s look at some more curiosity email subject line examples:

The Ultimate guide to [Topic]

Mastering [Topic] - A Step-by-Step approach

Our FREE guide to learning [Topic]

Our exclusive whitepaper on [Subject]

Unveiling your surprise gift inside

Discover the secret to [Desired Outcome]

[Business Name]: How to get an extra 10% off

The Secrets of [Topic] revealed!

[Product Name]: How to get 5X out of it

Announcing: The All-new [Product Name]

A behind the scenes look at [Product Name]

Guess who just bought [Product Name]

Special guest coming to our AMA this week

5 Reasons to NEVER offer discounts

[Topic]: 7 Tips to become a Pro

Your special invite: Join us for [Event Name]

Enter our online contest, [First Name]

5 FREE resources to get better at [Topic]

[Brand Name]: Your secret savings inside

Unlock your special offer [First Name]

Where to ship your free gift?

The wait is finally over ​​[First Name]

[First Name], your special offer here

Unlocking the hidden secrets of [Topic]

[Topic]: The untold story

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Open Sesame: Subject lines to get your emails read

Your perfect email won't matter if it won't be opened. Want some inspiration? Check these robust subject lines, designed for maximum opens of your promotional emails.
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