diff --git a/src/resources/filters/modules/typst_css.lua b/src/resources/filters/modules/typst_css.lua
index 6ef1b7d2d6..860766f0ce 100644
--- a/src/resources/filters/modules/typst_css.lua
+++ b/src/resources/filters/modules/typst_css.lua
@@ -593,6 +593,47 @@ local function quote(s)
   return '"' .. s .. '"'
 end
 
+local same_weights = {
+  'thin',
+  'light',
+  'normal',
+  'regular',
+  'medium',
+  'bold',
+  'black',
+}
+
+local weight_synonyms = {
+  ['ultra-light'] = 'extra-light',
+  ['demi-bold'] = 'semi-bold',
+  ['ultra-bold'] = 'extra-bold',
+}
+
+local dashed_weights = {
+  'extra-light',
+  'ultra-light',
+  'semi-bold',
+  'demi-bold',
+  'extra-bold',
+  'ultra-bold',
+}
+
+local function translate_font_weight(w, warnings)
+  if not w then return nil end
+  local num = tonumber(w)
+  if num and 1 <= num and num <= 1000 then
+    return num
+  elseif tcontains(same_weights, w) then
+    return w
+  elseif tcontains(dashed_weights, w) then
+    w = weight_synonyms[w] or w
+    return w:gsub('-', '')
+  else
+    output_warning(warnings, 'invalid font weight ' .. tostring(w))
+    return nil
+  end
+end
+
 local function translate_border_style(v, _warnings)
   local dash
   if v == 'none' then
@@ -718,6 +759,7 @@ return {
   translate_border_width = translate_border_width,
   translate_border_style = translate_border_style,
   translate_border_color = translate_border_color,
+  translate_font_weight = translate_font_weight,
   consume_width = consume_width,
   consume_style = consume_style,
   consume_color = consume_color
diff --git a/src/resources/filters/quarto-post/typst-brand-yaml.lua b/src/resources/filters/quarto-post/typst-brand-yaml.lua
index 51e78f993c..6389f0b900 100644
--- a/src/resources/filters/quarto-post/typst-brand-yaml.lua
+++ b/src/resources/filters/quarto-post/typst-brand-yaml.lua
@@ -51,6 +51,11 @@ function render_typst_brand_yaml()
     end
   end
 
+  local function quote_string(value)
+    if type(value) ~= 'string' then return value end
+    return '"' .. value .. '"'
+  end
+
   return {
     Pandoc = function(pandoc)
       local brand = param('brand')
@@ -82,10 +87,6 @@ function render_typst_brand_yaml()
           local decl = '// theme colors at opacity ' .. BACKGROUND_OPACITY .. '\n#let brand-color-background = ' .. to_typst_dict_indent(themebk)
           quarto.doc.include_text('in-header', decl)
         end
-        local function quote_string(value)
-          if type(value) ~= 'string' then return value end
-          return '"' .. value .. '"'
-        end
         local function conditional_entry(key, value, quote_strings)
           if quote_strings == null then quote_strings = true end
           if not value then return '' end
@@ -98,7 +99,7 @@ function render_typst_brand_yaml()
             quarto.doc.include_text('in-header', table.concat({
               '#set text(',
               -- '#show par: set text(', overrules #show heading!
-              conditional_entry('weight', base.weight),
+              conditional_entry('weight', _quarto.modules.typst.css.translate_font_weight(base.weight)),
               ')'
             }))
         end
@@ -117,7 +118,7 @@ function render_typst_brand_yaml()
             quarto.doc.include_text('in-header', table.concat({
               '#show heading: set text(',
               conditional_entry('font', headings.family),
-              conditional_entry('weight', headings.weight),
+              conditional_entry('weight', _quarto.modules.typst.css.translate_font_weight(headings.weight)),
               conditional_entry('style', headings.style),
               conditional_entry('fill', headings.color, false),
               ')'
@@ -138,7 +139,7 @@ function render_typst_brand_yaml()
             quarto.doc.include_text('in-header', table.concat({
               '#show raw.where(block: false): set text(',
               conditional_entry('font', monospaceInline.family),
-              conditional_entry('weight', monospaceInline.weight),
+              conditional_entry('weight', _quarto.modules.typst.css.translate_font_weight(monospaceInline.weight)),
               conditional_entry('size', monospaceInline.size, false),
               conditional_entry('fill', monospaceInline.color, false),
               ')'
@@ -157,7 +158,7 @@ function render_typst_brand_yaml()
           quarto.doc.include_text('in-header', table.concat({
             '#show raw.where(block: true): set text(',
             conditional_entry('font', monospaceBlock.family),
-            conditional_entry('weight', monospaceBlock.weight),
+            conditional_entry('weight', _quarto.modules.typst.css.translate_font_weight(monospaceBlock.weight)),
             conditional_entry('size', monospaceBlock.size, false),
             conditional_entry('fill', monospaceBlock.color, false),
             ')'
@@ -187,7 +188,7 @@ function render_typst_brand_yaml()
           link = link or {}
           quarto.doc.include_text('in-header', table.concat({
             '#show link: set text(',
-            conditional_entry('weight', link.weight),
+            conditional_entry('weight', _quarto.modules.typst.css.translate_font_weight(link.weight)),
             conditional_entry('fill', link.color or primaryColor, false),
             ')'
           }))
@@ -312,9 +313,11 @@ function render_typst_brand_yaml()
         headings = headings or {}
         local color = headings.color or foregroundColor
         color = color and pandoc.RawInline('typst', color)
+        local weight = _quarto.modules.typst.css.translate_font_weight(headings.weight or base.weight)
+        weight = weight and pandoc.RawInline('typst', tostring(quote_string(weight)))
         meta.brand.typography.headings = {
           family = headings.family or base.family,
-          weight = headings.weight or base.weight,
+          weight = weight,
           style = headings.style or base.style,
           decoration = headings.decoration or base.decoration,
           color = color,
diff --git a/tests/docs/smoke-all/typst/brand-yaml/typography/dashed-font-weights.qmd b/tests/docs/smoke-all/typst/brand-yaml/typography/dashed-font-weights.qmd
new file mode 100644
index 0000000000..5b41ee9ae4
--- /dev/null
+++ b/tests/docs/smoke-all/typst/brand-yaml/typography/dashed-font-weights.qmd
@@ -0,0 +1,44 @@
+---
+title: "Dashed font weights"
+format:
+  typst:
+    keep-typ: true
+brand:
+  typography:
+    base:
+      weight: ultra-light
+    headings:
+      weight: ultra-bold
+    monospace-inline:
+      weight: light
+    monospace-block:
+      weight: semi-bold
+_quarto:
+  tests:
+    typst:
+      ensureTypstFileRegexMatches:
+      -
+        - '#set text\(weight: "extralight", \)'
+        - 'heading-weight: "extrabold",'
+        - '#show raw.where\(block: false\): set text\(weight: "light", \)'
+        - '#show raw.where\(block: true\): set text\(weight: "semibold", \)'
+      - []
+      ensurePdfRegexMatches:
+      -
+        - 'base is extralight'
+        - 'heading-2 is extrabold'
+      - []
+
+---
+
+## heading-2 is `#context text.weight`{=typst}
+
+```
+def fact n:
+  if n == 1:
+    return 1
+  return n * fact(n-1)
+```
+
+base is `#context text.weight`{=typst} \
+{{< lipsum 1 >}}
\ No newline at end of file