5 Follow-Up Email Subject Lines that Actually Work

TLDR: Building and launching an email marketing campaign is a piece of cake these days. Write the content, maybe style it nicely, perhaps you’ll even add it to a flow system so that users are channeled depending on if they open an email or not, then hit launch. Campaign done.

Why Follow-Up Emails Matter

Follow-up emails are your opportunity to continue the conversation. Without them, many opportunities can flounder and, worse still, disappear altogether. There are many reasons why you might send a follow-up email; 

  • It might be to keep the contact going following an in-person meeting
  • It could be that you’ve gotten in touch with a great new sales prospect and want to keep in their mind
  • Perhaps you sent an email but didn’t receive a reply
  • You could just need to remind someone that they haven’t gotten back to you
  • Or you have reached the end of the road and need a reply before killing the conversation.

This list of reasons is just the start, but you can see that the purpose of follow-up emails is to get the reader to complete a certain action. This action can, sometimes, be incredibly important and therefore it’s worth getting the first impression, the subject line, right.

How to Write a Follow-Up Email Subject Line That Works

Writing the subject line is often the first step people complete after writing the user’s address, this doesn’t have to be the case. In fact, it’s often better to complete the subject line at the end. Write the content of the email first, then the subject line (now you know and understand exactly what you want from them), and then put in their address (this stops missends and the (no subject) nightmares.

Keep it brief

Remember mobile users! They’re on small screens which will cut off your lengthy, well-thought-out essay of a subject line. Aim for 6-10 words, but fewer works. More is often wasted. Size does matter here.

Personalization works wonders

People like to be spoken to as if they’re an actual person, not just another email address on a list. Remember that there is a human at the end of every inbox. A simple address by their name will make a tangible difference in open rate. Many email campaign software tools will allow personalization en masse.

Don’t write like a robot

Sound like a human, because that is what you are! Aim to sound friendly and as if you’re trying to have a conversation with the recipient. A great tip is to read your subject line out loud before sending. Do you sound normal or do you sound like a wired-up salesperson hungry for another commission? 

Test, test, test

Sending out a campaign with the same subject line and hoping it works is a fool’s errand. First of all, you have only one dataset to work with, secondly, you have nothing to compare it to so it can be judged successful or not. Segment your users into groups and send the same content but with different subject lines. See which performs better and which requires improvement, eventually, you’ll end up with a successful subject line with the data to prove it.


Making use of software that allows you to harness the power of automated follow ups can massively save time and effort. When working at scale, automation becomes less of a luxury and more of a necessity.

Follow Up Email Subject Line Examples

You haven’t received a reply – I forgot to mention…

This is a great way to reopen the conversation and psychologically puts the reader on the front foot as you (the sender) are the one who has made an error. It shows that you’re a genuine human, that you’re having a natural conversation, and that you’re not on the hard sell. Especially powerful when paired with a piece of content you can share.

When you want to keep in their mind – Lovely talking with you, [name]

Following a conversation, it could be a few days, a day, or even a few hours afterward, sending an email with this subject line shows that you were engaged with them and puts your name into their mind again. Personalization shows that you really appreciated the connection.

You really want a meeting – Meeting at 13:00, Thursday 5th

This is a bit of a shot in the dark but it does often work. In a world where people spend hours bouncing back and forth trying to merge diaries, some people appreciate a bit of forthrightness. It also often gets a reply, either in a positive way where they accept the request or a negative way where they say that they’re not available, but the dialogue has been opened and there’s an opportunity to find a meeting.

You need help – Could you help me, please?

Asking a direct question in an empathetic way often gets a positive response.

The final shot – What can I do to get a reply?

You’ve tried multiple times, but they haven’t responded and this is your last ditch effort before closing the loop and giving up. A straightforward, honest question, with a bit of humor, goes a long way. If they still don’t reply, then at least you’ve got closure.

Key Takeaways on Follow Up Subjects for Emails

Follow-up subject lines are an opportunity to grab a response and keep lines of communication open. Remember that there are different subject lines for different occasions and mixing them up can have a powerful effect.

  • Automating the process of following up can be a game changer for productivity and efficiency.
  • Test and adapt, track the metrics of various lines and use those that have the best figures.