diff --git a/lib/shared/markdown.js b/lib/shared/markdown.js
--- a/lib/shared/markdown.js
+++ b/lib/shared/markdown.js
@@ -87,6 +87,7 @@
 
 const blockQuoteRegex: RegExp = /^( *>[^\n]+(?:\n[^\n]+)*)(?:\n|$)/;
 const blockQuoteStripFollowingNewlineRegex: RegExp = /^( *>[^\n]+(?:\n[^\n]+)*)(?:\n|$){2}/;
+const maxNestedQuotations = 5;
 
 const urlRegex: RegExp = /^(https?:\/\/[^\s<]+[^<.,:;"')\]\s])/i;
 
@@ -231,6 +232,7 @@
   codeBlockStripTrailingNewlineRegex,
   fenceRegex,
   fenceStripTrailingNewlineRegex,
+  maxNestedQuotations,
   jsonMatch,
   jsonPrint,
   matchList,
diff --git a/native/markdown/rules.react.js b/native/markdown/rules.react.js
--- a/native/markdown/rules.react.js
+++ b/native/markdown/rules.react.js
@@ -7,7 +7,9 @@
 import * as SimpleMarkdown from 'simple-markdown';
 
 import { relativeMemberInfoSelectorForMembersOfThread } from 'lib/selectors/user-selectors';
+import type { State } from 'lib/shared/markdown';
 import * as SharedMarkdown from 'lib/shared/markdown';
+import { maxNestedQuotations } from 'lib/shared/markdown';
 import type { RelativeMemberInfo } from 'lib/types/thread-types';
 
 import { useSelector } from '../redux/redux-utils';
@@ -215,17 +217,24 @@
     blockQuote: {
       ...SimpleMarkdown.defaultRules.blockQuote,
       // match end of blockQuote by either \n\n or end of string
-      match: SimpleMarkdown.blockRegex(
-        SharedMarkdown.blockQuoteStripFollowingNewlineRegex,
-      ),
+      match: (source: string, state: State) => {
+        if (state.quotationsCount >= maxNestedQuotations) {
+          return undefined;
+        }
+        return SharedMarkdown.blockQuoteRegex.exec(source);
+      },
       parse(
         capture: SharedMarkdown.Capture,
         parse: SharedMarkdown.Parser,
         state: SharedMarkdown.State,
       ) {
         const content = capture[1].replace(/^ *> ?/gm, '');
+        const currentQuotationsCount = state.quotationsCount ?? 0;
         return {
-          content: parse(content, state),
+          content: parse(content, {
+            ...state,
+            quotationsCount: currentQuotationsCount + 1,
+          }),
         };
       },
       // eslint-disable-next-line react/display-name
diff --git a/web/markdown/rules.react.js b/web/markdown/rules.react.js
--- a/web/markdown/rules.react.js
+++ b/web/markdown/rules.react.js
@@ -6,6 +6,8 @@
 
 import { relativeMemberInfoSelectorForMembersOfThread } from 'lib/selectors/user-selectors';
 import * as SharedMarkdown from 'lib/shared/markdown';
+import { maxNestedQuotations } from 'lib/shared/markdown';
+import type { State } from 'lib/shared/markdown.js';
 import type { RelativeMemberInfo } from 'lib/types/thread-types';
 
 import { useSelector } from '../redux/redux-utils';
@@ -78,15 +80,24 @@
     blockQuote: {
       ...SimpleMarkdown.defaultRules.blockQuote,
       // match end of blockQuote by either \n\n or end of string
-      match: SimpleMarkdown.blockRegex(SharedMarkdown.blockQuoteRegex),
+      match: (source: string, state: State) => {
+        if (state.quotationsCount >= maxNestedQuotations) {
+          return undefined;
+        }
+        return SharedMarkdown.blockQuoteRegex.exec(source);
+      },
       parse(
         capture: SharedMarkdown.Capture,
         parse: SharedMarkdown.Parser,
         state: SharedMarkdown.State,
       ) {
         const content = capture[1].replace(/^ *> ?/gm, '');
+        const currentQuotationsCount = state.quotationsCount ?? 0;
         return {
-          content: parse(content, state),
+          content: parse(content, {
+            ...state,
+            quotationsCount: currentQuotationsCount + 1,
+          }),
         };
       },
     },