Quick answer: Respond is broader — it means to react in any way to something, verbally or non-verbally: The patient responded well to the treatment. Reply is more specific and means to give a verbal or written answer to a question, message, or letter: She replied to his email within the hour. Remember: RESPOND = react in any way (broader); REPLY = give a verbal or written answer (narrower). For a fuller definition, see the Cambridge Dictionary entry for ‘respond’.
Comparison Table
| Word | Part of Speech | Meaning | Example |
|---|---|---|---|
| respond | verb | to react to something; to give any kind of answer or reaction | She responded by shaking her head. |
| reply | verb / noun | to say or write something in answer to a question, letter, or message | He replied with a brief email. |
Using Respond
Respond is the broader of the two words. It means to react — and the reaction can be physical, emotional, or verbal. You can respond to a medical treatment, respond to a crisis, or respond to a question.
The tumour responded well to chemotherapy.
Emergency services responded within minutes.
She responded to the insult by leaving the room.
How did he respond when you told him the news?
Respond is followed by to: you respond to something. It is not followed by a direct object without a preposition.
Using Reply
Reply is more specific: it always involves a verbal or written answer to a question, message, letter, or accusation. There is always an exchange of communication implied.
Please reply to this email by Friday.
“I’m not sure,” she replied.
He hasn’t replied to any of my messages.
The company replied with a formal letter.
As a noun, a reply is an answer or response: I’m still waiting for a reply. Respond has no equivalent noun; the noun form of respond is response.
Reply To vs Reply With
I replied to her question with a smile. (replied to = gave an answer to)
She replied with a one-word answer. (replied with = the form of the reply)
Key Differences
- Scope: respond is broader (any reaction); reply is narrower (verbal/written answer).
- Non-verbal actions: you can respond non-verbally (respond by nodding); you cannot reply non-verbally.
- Medical and scientific use: respond is used (respond to treatment, respond to stimuli); reply is not.
- Noun forms: response (from respond); reply (its own noun).
Memory Tip
RESPOND → think of emergency responders: they react quickly and in many ways.
REPLY → think of reply all in email: specifically sending a written or spoken answer.
Common Mistakes
✗ The patient replied well to the medicine.
✓ The patient responded well to the medicine.
✗ She responded my question.
✓ She responded to my question.
✗ I haven’t received a response to my text message yet. (not wrong, but sounds overly formal)
✓ I haven’t received a reply to my text message yet. (more natural in everyday contexts)
Also confusing: Inquire vs Investigate, Permit vs Allow, Accept vs Except. Browse all confusing word pairs →
Quick Check: Respond or Reply?
Four questions — choose the correct word for each sentence.
1. “The patient ___ well to the new treatment.”
2. “Please ___ to this email by tomorrow.”
3. “Emergency services ___ to the scene within minutes.”
4. “‘I don’t know,’ he ___.”
Frequently Asked Questions
What is the difference between respond and reply?
Respond is broader: it means to react in any way — physically, emotionally, or verbally: “The patient responded to treatment.” Reply is more specific: it means to give a verbal or written answer to a question, message, or letter: “She replied to his email.” You cannot reply non-verbally, but you can respond non-verbally.
Can respond and reply be used interchangeably?
In communication contexts (emails, letters, questions), both often work: “Please respond to my email” and “Please reply to my email” mean the same thing. However, for medical, scientific, or non-verbal reactions, only respond is correct. For quoting spoken dialogue, reply is far more natural: “'No,' she replied” rather than “'No,' she responded.”
What are the noun forms of respond and reply?
The noun form of respond is response: “We received a positive response.” The noun form of reply is simply reply: “I’m still waiting for a reply.” In formal writing, response is broader and covers any kind of reaction; reply specifically refers to an answer given verbally or in writing.
Does respond require a preposition?
Yes. Respond is followed by to: “respond to a question,” “respond to treatment,” “respond to a crisis.” You cannot say “respond a question” without the preposition. Reply can be used with or without to: “She replied to him” or “'Yes,' she replied.”
Is “in reply” or “in response” more formal?
Both are formal phrases used in writing. “In response to your letter...” is the standard opening in formal business letters. “In reply to your enquiry...” is equally correct and common. In practice, both are widely used interchangeably in professional correspondence. “In reply” slightly suggests a direct verbal or written exchange; “in response” is broader.
Can you use “replied” as a speech tag?
Yes. Replied is one of the most natural speech tags when quoting dialogue: “‘I don’t know,’ she replied.” It implies the character is giving an answer to what someone else said. You can also use responded as a speech tag: “‘I don’t know,’ she responded.” Both are correct; replied is slightly more specific to answering, while responded can include any kind of reaction.
What does “first responder” mean?
A first responder is a person who is among the first to arrive and provide assistance at an emergency scene, such as a paramedic, firefighter, or police officer. The term uses respond in the sense of reacting to an emergency situation. You would not say “first replier” — reply does not work in this context because the reaction is physical and situational, not a verbal answer.
What are common collocations with respond?
Common collocations: respond to a question/crisis/treatment/complaint/challenge, respond positively/negatively, fail to respond, respond appropriately, respond with (a nod/smile/action), first responder. In formal writing: “We will respond to your inquiry within 24 hours.” In science: “The cells responded to the stimulus.”
What are common collocations with reply?
Common collocations: reply to an email/letter/message/question, receive a reply, await a reply, prompt reply, reply in writing, RSVP (which stands for the French répondez s’il vous plaît — “please reply”). Note that “reply all” is a standard function in email. In speech: “he replied,” “she replied angrily.”
How are respond and reply used in IELTS?
Both words appear in IELTS writing and reading, especially in communication, science, and social topics. In academic writing, respond is more common because of its broader scope: “Participants responded to the questionnaire.” Reply is common in General Training letter writing: “I am writing in reply to your advertisement.” Using both correctly demonstrates C1-level vocabulary range.