40 of the Best Email Subject Lines We've Ever Seen

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I’d venture to guess you get tons of emails in your inbox every day.

From coupons to daily deal sites, from newsletters to your mother wanting to know when you plan to visit — it’s a lot to sift through, never mind actually open.

So what makes you want to take that extra step to actually open an email? Often, it’s the subject line. After all, it’s your very first impression of the email. From that first impression, you’ll do your best to judge the content inside.

If you’re an email marketer, or just someone who happens to send emails on behalf of your company, you don’t want to be one of those ignored (or deleted) emails in your subscribers’ inboxes. You’ve got to make sure your email subject lines are top-notch — and what better way to learn how to do that than by examining some great examples of subject lines?

Let’s take a look at a few examples that, old or new, we’re crazy about — plus what makes them so great.

(While you’re at it, check out our Out-of-Office Email Generator to make your email address even more delightful to your contacts.)

1. “Uh-oh, your prescription is expiring”

Sender: Warby Parker

Not too long ago, a HubSpot alum received this email two weeks before he needed to renew his prescription — talk about great timing. And when your eye prescription is expiring, it happens to be an excellent time to upgrade your glasses. By sending an email at the right time, Warby Parker increased its chances of this email getting opened.

But timing isn’t the sole reason we included this example. This subject line is brilliant because it appeared at the right time and with the right tone. Using conversational words like “uh-oh,” keeping the subject line sentence case, and leaving out the period at the end, the subject line comes across as helpful and friendly — not as a company trying to upsell you.

2. “Best of Groupon: The Deals That Make Us Proud (Unlike Our Nephew, Steve)”

Sender: Groupon

It’s hard to be funny in your marketing, but Groupon’s one of those brands that seems to nail it again and again. After all, who can forget this classic unsubscribe video?

This subject line is no exception. The quip, “(Unlike Our Nephew Steve),” actually had us

laughing out loud. Why? It’s completely unexpected. The first part of the subject line looks like a typical subject line you’d get from Groupon, highlighting a new deal. The parenthetical content? Not so much — making this one a delightful gem to find in your inbox.