diff --git a/src/components/app-body/posts/index.js b/src/components/app-body/posts/index.js
index a179e43..b974758 100644
--- a/src/components/app-body/posts/index.js
+++ b/src/components/app-body/posts/index.js
@@ -11,6 +11,7 @@ import { Container, Row, Col, Spinner, Table, Button } from 'react-bootstrap'
 import MemoDb from '../../../services/memo-db'
 import AppUtil from '../../../util'
 import PostReplyCount from '../../post-reply-count'
+import PostThreadModal from '../../post-thread-modal'
 import '../../../App.css'
 
 const appUtil = new AppUtil()
@@ -34,6 +35,18 @@ function RecentPosts () {
   const [posts, setPosts] = useState([])
   const [pagination, setPagination] = useState(null)
   const [offset, setOffset] = useState(0)
+  const [threadTxid, setThreadTxid] = useState(null)
+  const [showThreadModal, setShowThreadModal] = useState(false)
+
+  const openThread = (txid) => {
+    setThreadTxid(txid)
+    setShowThreadModal(true)
+  }
+
+  const closeThread = () => {
+    setShowThreadModal(false)
+    setThreadTxid(null)
+  }
 
   useEffect(() => {
     const loadPosts = async () => {
@@ -117,7 +130,10 @@ function RecentPosts () {
                     </td>
                     <td>
                       <div>{post.text}</div>
-                      <PostReplyCount count={post.replyCount ?? 0} />
+                      <PostReplyCount
+                        count={post.replyCount ?? 0}
+                        onClick={() => openThread(post.txid)}
+                      />
                     </td>
                     <td>{post.blockHeight}</td>
                     <td>{formatSeen(post.seen)}</td>
@@ -156,6 +172,12 @@ function RecentPosts () {
           )}
         </Col>
       </Row>
+
+      <PostThreadModal
+        show={showThreadModal}
+        txid={threadTxid}
+        onHide={closeThread}
+      />
     </Container>
   )
 }
diff --git a/src/components/app-body/profile/index.js b/src/components/app-body/profile/index.js
index 167a9b9..fb1b623 100644
--- a/src/components/app-body/profile/index.js
+++ b/src/components/app-body/profile/index.js
@@ -9,6 +9,7 @@ import Jdenticon from '@chris.troutner/react-jdenticon'
 
 import MemoDb from '../../../services/memo-db'
 import PostReplyCount from '../../post-reply-count'
+import PostThreadModal from '../../post-thread-modal'
 import '../../../App.css'
 import './profile.css'
 
@@ -53,6 +54,18 @@ function Profile () {
   const [profilePicUrl, setProfilePicUrl] = useState(null)
   const [posts, setPosts] = useState([])
   const [pagination, setPagination] = useState(null)
+  const [threadTxid, setThreadTxid] = useState(null)
+  const [showThreadModal, setShowThreadModal] = useState(false)
+
+  const openThread = (txid) => {
+    setThreadTxid(txid)
+    setShowThreadModal(true)
+  }
+
+  const closeThread = () => {
+    setShowThreadModal(false)
+    setThreadTxid(null)
+  }
 
   useEffect(() => {
     const loadProfile = async () => {
@@ -138,13 +151,22 @@ function Profile () {
                     <span className='profile-post-block ms-2'>Block {post.blockHeight}</span>
                   </div>
                   <Card.Text className='profile-post-text'>{post.text}</Card.Text>
-                  <PostReplyCount count={post.replyCount ?? 0} />
+                  <PostReplyCount
+                    count={post.replyCount ?? 0}
+                    onClick={() => openThread(post.txid)}
+                  />
                 </Card.Body>
               </Card>
             ))}
           </Col>
         </Row>
       )}
+
+      <PostThreadModal
+        show={showThreadModal}
+        txid={threadTxid}
+        onHide={closeThread}
+      />
     </Container>
   )
 }
diff --git a/src/components/post-reply-count/index.js b/src/components/post-reply-count/index.js
index 0294fd7..cf17f07 100644
--- a/src/components/post-reply-count/index.js
+++ b/src/components/post-reply-count/index.js
@@ -8,11 +8,28 @@ import { faComment } from '@fortawesome/free-solid-svg-icons'
 
 import './post-reply-count.css'
 
-function PostReplyCount ({ count = 0 }) {
+function PostReplyCount ({ count = 0, onClick }) {
   const label = count === 1 ? '1 reply' : `${count} replies`
+  const clickable = count > 0 && typeof onClick === 'function'
+  const title = clickable ? `${label} — click to view` : label
+
+  const handleKeyDown = (event) => {
+    if (clickable && (event.key === 'Enter' || event.key === ' ')) {
+      event.preventDefault()
+      onClick()
+    }
+  }
 
   return (
-    <div className='post-reply-count' title={label} aria-label={label}>
+    <div
+      className={`post-reply-count${clickable ? ' post-reply-count-clickable' : ''}`}
+      title={title}
+      aria-label={title}
+      role={clickable ? 'button' : undefined}
+      tabIndex={clickable ? 0 : undefined}
+      onClick={clickable ? onClick : undefined}
+      onKeyDown={clickable ? handleKeyDown : undefined}
+    >
       <FontAwesomeIcon icon={faComment} className='post-reply-count-icon' />
       <span className='post-reply-count-number'>{count}</span>
     </div>
diff --git a/src/components/post-reply-count/post-reply-count.css b/src/components/post-reply-count/post-reply-count.css
index b682720..c9c9f3b 100644
--- a/src/components/post-reply-count/post-reply-count.css
+++ b/src/components/post-reply-count/post-reply-count.css
@@ -10,3 +10,11 @@
 .post-reply-count-icon {
   font-size: 0.9rem;
 }
+
+.post-reply-count-clickable {
+  cursor: pointer;
+}
+
+.post-reply-count-clickable:hover {
+  color: #28a745;
+}
diff --git a/src/components/post-thread-modal/index.js b/src/components/post-thread-modal/index.js
new file mode 100644
index 0000000..b89fbe1
--- /dev/null
+++ b/src/components/post-thread-modal/index.js
@@ -0,0 +1,86 @@
+/*
+  Modal displaying a post and its nested reply thread.
+*/
+
+import React, { useState, useEffect } from 'react'
+import { Modal, Spinner } from 'react-bootstrap'
+
+import MemoDb from '../../services/memo-db'
+import PostThreadNode from './post-thread-node'
+import './post-thread-modal.css'
+
+function PostThreadModal ({ show, txid, onHide }) {
+  const [loading, setLoading] = useState(false)
+  const [error, setError] = useState(null)
+  const [thread, setThread] = useState(null)
+
+  useEffect(() => {
+    if (!show || !txid) {
+      return undefined
+    }
+
+    let cancelled = false
+
+    const loadThread = async () => {
+      setLoading(true)
+      setError(null)
+      setThread(null)
+
+      try {
+        const memoDb = new MemoDb()
+        const data = await memoDb.getPostThread(txid)
+        if (!cancelled) {
+          setThread(data.post || null)
+        }
+      } catch (err) {
+        if (!cancelled) {
+          const message = err.response?.data?.message || err.message || 'Failed to load replies'
+          setError(message)
+        }
+      }
+
+      if (!cancelled) {
+        setLoading(false)
+      }
+    }
+
+    loadThread()
+
+    return () => {
+      cancelled = true
+    }
+  }, [show, txid])
+
+  const handleHide = () => {
+    setThread(null)
+    setError(null)
+    onHide()
+  }
+
+  return (
+    <Modal show={show} onHide={handleHide} size='lg' scrollable centered>
+      <Modal.Header closeButton>
+        <Modal.Title>Post thread</Modal.Title>
+      </Modal.Header>
+      <Modal.Body className='post-thread-modal-body'>
+        {loading && (
+          <div className='text-center my-4'>
+            <Spinner animation='border' role='status' variant='primary'>
+              <span className='visually-hidden'>Loading replies...</span>
+            </Spinner>
+          </div>
+        )}
+
+        {error && !loading && (
+          <p className='text-danger mb-0'>{error}</p>
+        )}
+
+        {!loading && !error && thread && (
+          <PostThreadNode post={thread} isRoot />
+        )}
+      </Modal.Body>
+    </Modal>
+  )
+}
+
+export default PostThreadModal
diff --git a/src/components/post-thread-modal/post-thread-modal.css b/src/components/post-thread-modal/post-thread-modal.css
new file mode 100644
index 0000000..75139fc
--- /dev/null
+++ b/src/components/post-thread-modal/post-thread-modal.css
@@ -0,0 +1,48 @@
+.post-thread-modal-body {
+  max-height: 70vh;
+}
+
+.post-thread-node {
+  margin-top: 0.75rem;
+}
+
+.post-thread-node-root {
+  margin-top: 0;
+}
+
+.post-thread-node-inner {
+  border: 1px solid #dee2e6;
+  border-radius: 4px;
+  padding: 0.75rem 1rem;
+  background: #fff;
+}
+
+.post-thread-node-root > .post-thread-node-inner {
+  border-color: #ced4da;
+}
+
+.post-thread-node-header {
+  font-size: 0.85rem;
+  margin-bottom: 0.5rem;
+}
+
+.post-thread-node-author {
+  font-family: monospace;
+  font-size: 0.8rem;
+  text-decoration: none;
+}
+
+.post-thread-node-author:hover {
+  text-decoration: underline;
+}
+
+.post-thread-node-replied {
+  font-style: italic;
+}
+
+.post-thread-node-text {
+  white-space: pre-wrap;
+  word-break: break-word;
+  font-size: 0.95rem;
+  line-height: 1.5;
+}
diff --git a/src/components/post-thread-modal/post-thread-node.js b/src/components/post-thread-modal/post-thread-node.js
new file mode 100644
index 0000000..1d3b440
--- /dev/null
+++ b/src/components/post-thread-modal/post-thread-node.js
@@ -0,0 +1,49 @@
+/*
+  Single post node in a reply thread (recursive).
+*/
+
+import React from 'react'
+import { Link } from 'react-router-dom'
+
+function formatSeen (seen) {
+  if (!seen) return ''
+  const ms = seen > 1e12 ? seen : seen * 1000
+  return new Date(ms).toLocaleString()
+}
+
+function truncateAddr (addr, maxLen = 20) {
+  if (!addr || addr.length <= maxLen) return addr
+  const half = Math.floor((maxLen - 3) / 2)
+  return `${addr.slice(0, half)}...${addr.slice(-half)}`
+}
+
+function PostThreadNode ({ post, depth = 0, isRoot = false }) {
+  if (!post) return null
+
+  return (
+    <div
+      className={`post-thread-node${isRoot ? ' post-thread-node-root' : ''}`}
+      style={{ marginLeft: depth > 0 ? `${Math.min(depth, 8) * 1.25}rem` : undefined }}
+    >
+      <div className='post-thread-node-inner'>
+        <div className='post-thread-node-header text-muted'>
+          <Link
+            to={`/profile/${encodeURIComponent(post.addr)}`}
+            className='post-thread-node-author'
+            title={post.addr}
+          >
+            {truncateAddr(post.addr, 24)}
+          </Link>
+          {!isRoot && <span className='post-thread-node-replied ms-1'>replied</span>}
+          <span className='post-thread-node-seen ms-2'>{formatSeen(post.seen)}</span>
+        </div>
+        <div className='post-thread-node-text'>{post.text}</div>
+        {(post.replies || []).map((reply) => (
+          <PostThreadNode key={reply.txid} post={reply} depth={depth + 1} />
+        ))}
+      </div>
+    </div>
+  )
+}
+
+export default PostThreadNode
diff --git a/src/services/memo-db.js b/src/services/memo-db.js
index 1704aec..251ed0f 100644
--- a/src/services/memo-db.js
+++ b/src/services/memo-db.js
@@ -79,6 +79,19 @@ class MemoDb {
       throw err
     }
   }
+
+  async getPostThread (txid) {
+    try {
+      const result = await this.axios.get(
+        `${config.backend}/posts/${encodeURIComponent(txid)}/thread`
+      )
+
+      return result.data
+    } catch (err) {
+      console.error('Error in getPostThread()')
+      throw err
+    }
+  }
 }
 
 export default MemoDb