leave behind

2 meanings

Meanings
  1. 1 forget to take something with you when you leave a place B1
  2. 2 make much more progress than someone else B2
1 leave sth behind

forget to take something with you when you leave a place

B1

What does "leave behind" mean in this sense?

When you leave a place and accidentally forget to take something with you, you have left it behind. The object stays where you were — on a table, at a hotel, on a bus — while you move on without it. This phrasal verb puts the focus on the physical situation: the thing is still there in the place you left, not just forgotten in your mind. It is slightly more descriptive than simply saying 'forgot', because it makes clear that the object remained somewhere specific. You will hear and read it in everyday conversations about travel, commuting, and daily life.

Examples

How to use it

leave + object + behind

The most common pattern, with a noun object placed between the verb and the particle.

He left his jacket behind at the café.

leave behind + object

When the object is a noun, you can also place it after 'behind' — both orders are natural.

She nearly left behind her passport on the way to the airport.

leave + pronoun + behind

When the object is a pronoun, it must go between the verb and the particle — never after 'behind'.

I checked my bag and realised I'd left it behind at the hotel.

be left behind

The passive form is used when the focus is on the forgotten item rather than the person who forgot it.

A laptop was left behind in the meeting room and handed in to reception.

make sure you don't leave + object + behind

This fixed-sounding reminder pattern is very common in instructions and travel advice.

Before you get off the train, make sure you don't leave anything behind.

Common Collocations

leave phone behindleave keys behindleave bag behindleave wallet behindleave passport behindleave umbrella behind

Common Mistakes

Pronoun placement

When you use a pronoun like 'it' or 'them', it must go between 'leave' and 'behind'. Placing it after 'behind' is ungrammatical.

I left behind it on the bus.
I left it behind on the bus.
Confusing 'leave behind' with 'leave out'

'Leave behind' means you forgot to take a physical object when you departed from somewhere. 'Leave out' means you omitted something from a list, group, or activity — not that you forgot to pack it.

I left out my charger when I packed my suitcase.
I left my charger behind when I packed my suitcase.
Using the present continuous

This phrasal verb sounds unnatural in the present continuous. Use the simple past, present perfect, or simple present instead.

I am leaving my keys behind all the time.
I leave my keys behind all the time.

Usage

This phrasal verb is neutral and equally common in spoken and written British and American English. It is slightly more descriptive than simply saying 'forgot', as it emphasises that the object remained at the place you left.

2 leave sb behind

make much more progress than someone else

B2

Sense 2: What does "leave sb behind" mean?

This sense of 'leave behind' describes a situation where one person, group, company, or force makes so much more progress than another that a significant gap opens up between them. It is closely associated with discussions of inequality, economic change, and technological disruption — for example, when new technologies advance faster than certain workers can adapt, those workers are left behind. The phrase puts the focus on the faster party or force creating the gap, rather than on the slower party struggling to keep up. The passive form 'be left behind' or 'get left behind' is extremely common with this meaning and has become almost a fixed expression in journalism and political speech. You will often hear it applied to entire communities or social groups, as in phrases like 'those left behind by globalisation' or 'regions left behind by the digital economy'.

Examples

How to use it

subject + leave + object + behind

The most common active pattern, where the faster party or force is the subject and the group being surpassed is the object.

The rapid rise of e-commerce is leaving many small retailers behind.

subject + leave + pronoun + behind

When the object is a pronoun, it must always go between the verb and 'behind' — it cannot follow 'behind'.

Other economies grew so fast that the region simply couldn't keep up — growth left them behind.

be/get left behind (by + agent)

The passive is extremely common with this sense and is often the most natural choice when the focus is on the group being disadvantaged rather than the force outpacing them.

Younger graduates are advancing quickly, and older employees risk being left behind.

feel left behind

Used to describe the subjective experience of a person or community that perceives itself as falling behind others or being excluded from progress.

Many people in former industrial towns feel left behind by the shift to a knowledge-based economy.

those/people left behind (by + agent)

A near-fixed pattern used to refer collectively to the group that has been surpassed, especially in political or sociological contexts.

The government pledged new investment to support those left behind by decades of deindustrialisation.

Common Collocations

workers left behindleft behind by technologyrural communities left behindleave rivals behindfeel left behindrisk being left behind

Common Mistakes

Pronoun placement

When the object is a pronoun, it must sit between the verb and 'behind'. Placing it after 'behind' is a common error.

The economic boom left behind them.
The economic boom left them behind.
Confusing 'leave behind' with 'fall behind'

'Leave behind' focuses on the faster force or party that is outpacing others, while 'fall behind' focuses on the perspective of the group losing ground. Mixing up the subjects of these two verbs produces an unnatural sentence.

The struggling factories left behind in production.
The struggling factories fell behind in production. / The new competitors left the struggling factories behind.
Using this sense with physical objects

When an inanimate object is left somewhere accidentally, that is a different meaning of 'leave behind' (to forget something). In this sense of outpacing or surpassing, the object should be a person, group, community, or organisation.

Automation left behind the old machinery.
Automation left behind the workers who depended on old machinery.

Usage

This phrasal verb is neutral in register and very common in journalism, politics, and everyday conversation about inequality or competition. The passive form 'be/get left behind' is especially frequent — so frequent that learning it as a fixed pattern is highly recommended.

Frequently Asked Questions

Does 'leave behind' always mean forgetting something?

No — the same form can have a different meaning, such as when someone or something is left at a disadvantage while others move forward. However, that is a separate sense. When the object is a physical item like a phone or wallet, it almost always means forgetting to take it.

Is 'leave behind' stronger or different from just saying 'forget'?

They are very similar, but 'leave behind' adds a little more detail. It tells you not just that you forgot, but that the object stayed in the place you left. Saying 'I left my umbrella behind at the office' paints a clearer picture than simply 'I forgot my umbrella'.

Can I use 'leave behind' in a notice or written message?

Yes, it works naturally in both spoken and written English. You might see it in lost property notices, travel tips, or reminder signs — for example, 'Please check you have not left any belongings behind.'

What kinds of things can I use as the object of 'leave behind'?

In this sense, the object is always a physical, portable item — things like a phone, keys, wallet, umbrella, passport, or charger. Abstract ideas or people as objects belong to a different meaning of this phrasal verb.

Can I add adverbs like 'accidentally' or 'nearly' to 'leave behind'?

Yes, these adverbs are very natural with this phrasal verb. 'I accidentally left my bag behind' or 'I nearly left my ticket behind' are both common and sound very natural in everyday speech.

Is 'be left behind' more common than 'get left behind'?

Both are correct and very frequent with this meaning. 'Be left behind' is slightly more neutral and is common in formal writing and journalism, while 'get left behind' sounds slightly more informal and is common in everyday speech. In most contexts, you can use either.

Can 'leave behind' in this sense be used without an object?

Not in the active voice — you need to say who or what is being surpassed. However, in the passive ('be left behind' or 'get left behind'), no object is needed because the group being surpassed is already the subject of the sentence.

Does this phrasal verb always mean someone is making progress unfairly or negatively?

Not necessarily — it simply describes a widening gap in progress. In a competitive business context, for example, 'leave rivals behind' is neutral or even positive from the winner's perspective. The negative connotation tends to appear when the context involves vulnerable groups or inequality.

Is 'leave behind' in this sense formal or informal?

It is neutral in register and works in a wide range of contexts — from newspaper articles and political speeches to everyday conversation. The phrase 'no one gets left behind' is a well-known political slogan, which shows how naturally it crosses between formal and informal use.

Can I use this phrasal verb to talk about one person outpacing another in a competition or career?

Yes, absolutely. While it is especially common when talking about large groups and social inequality, it works just as well for individuals or companies — for example, 'She worked so hard that she quickly left her colleagues behind' or 'The startup left its rivals behind within two years'.

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