diff --git a/packages/assembler/lib/produce-aggregate-document.js b/packages/assembler/lib/produce-aggregate-document.js
index fc685633c87d0c847ae4d373186a5700ac9152d3..3a4025a49f9a66b98a70d09ec30cf90d3bc5a53e 100644
--- a/packages/assembler/lib/produce-aggregate-document.js
+++ b/packages/assembler/lib/produce-aggregate-document.js
@@ -315,7 +315,7 @@ function aggregateAsciiDoc (
           return
         }
         let blockStyle = sectionMergeStrategy === 'discrete' ? 'discrete' : undefined
-        lines[idx] = lines[idx].replace(/^=+ (.+)/, (_, rest) => {
+        lines[idx] = lines[idx].replace(/^[=#]+ (.+)/, (_, rest) => {
           let targetMarkerLength = block.level + 1 + level + (enclosed ? 1 : 0)
           if (targetMarkerLength > 6) {
             targetMarkerLength = 6
diff --git a/packages/assembler/test/produce-aggregate-documents-test.js b/packages/assembler/test/produce-aggregate-documents-test.js
index 9bd49ad208e4a6a8d6543ac2cbab94d23f4bc489..dc6572fa513be7a4a01a04ec7613b939044e0a45 100644
--- a/packages/assembler/test/produce-aggregate-documents-test.js
+++ b/packages/assembler/test/produce-aggregate-documents-test.js
@@ -90,6 +90,10 @@ describe('produceAggregateDocuments()', () => {
     await runScenario('process-asciidoc-table-cell', __dirname)
   })
 
+  it('should process markdown section headings', async () => {
+    await runScenario('markdown-style-section-headings', __dirname)
+  })
+
   it('should remove source-highlighter attribute on aggregate document if not specified', async () => {
     const { loadAsciiDoc, contentCatalog, assemblerConfig } = await loadScenario('insert-page', __dirname)
     const aggregateDocuments = await produceAggregateDocuments(loadAsciiDoc, contentCatalog, assemblerConfig)
diff --git a/packages/assembler/test/scenarios/markdown-style-section-headings/data.yml b/packages/assembler/test/scenarios/markdown-style-section-headings/data.yml
new file mode 100644
index 0000000000000000000000000000000000000000..321a32dfe71ad6f7faabc6cb66cee535c0177b75
--- /dev/null
+++ b/packages/assembler/test/scenarios/markdown-style-section-headings/data.yml
@@ -0,0 +1,12 @@
+name: the-component
+version: '1.0'
+title: The Component
+navigation:
+  items:
+  - content: xref:the-page.adoc[The Page Title]
+files:
+- relative: the-page.adoc
+  contents: |-
+    = The Page Title
+
+    ## First Section
diff --git a/packages/assembler/test/scenarios/markdown-style-section-headings/expects/the-component.adoc b/packages/assembler/test/scenarios/markdown-style-section-headings/expects/the-component.adoc
new file mode 100644
index 0000000000000000000000000000000000000000..ceab70c50946f93775b49ec0d08cf701fe5dd88d
--- /dev/null
+++ b/packages/assembler/test/scenarios/markdown-style-section-headings/expects/the-component.adoc
@@ -0,0 +1,22 @@
+= The Component
+v1.0
+:doctype: book
+:page-component-name: the-component
+:page-component-version: 1.0
+:page-version: {page-component-version}
+:page-component-display-version: 1.0
+:page-component-title: The Component
+
+:docname: the-page
+:page-module: ROOT
+:page-relative-src-path: the-page.adoc
+:page-origin-url: https://github.com/acme/the-component
+:page-origin-start-path:
+:page-origin-refname: v1.0
+:page-origin-reftype: branch
+:page-origin-refhash: a00000000000000000000000000000000000000z
+[#the-page:::]
+== The Page Title
+
+[discrete#the-page:::_first_section]
+=== First Section