diff --git a/packages/pdf/src/templates/onyx/OnyxPage.test.tsx b/packages/pdf/src/templates/onyx/OnyxPage.test.tsx
new file mode 100644
index 000000000..e06961ff6
--- /dev/null
+++ b/packages/pdf/src/templates/onyx/OnyxPage.test.tsx
@@ -0,0 +1,73 @@
+import type { TextItem } from "pdfjs-dist/types/src/display/api";
+import { describe, expect, it } from "vitest";
+import { renderToBuffer } from "@react-pdf/renderer";
+import { getDocument } from "pdfjs-dist/legacy/build/pdf.mjs";
+import { act, createElement } from "react";
+import { defaultResumeData } from "@reactive-resume/schema/resume/default";
+import { ResumeDocument } from "../../document";
+
+const PICTURE =
+	"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mP8/x8AAwMCAO+a1ioAAAAASUVORK5CYII=";
+const HEADLINE = Array.from({ length: 12 }, (_, index) => `Experience ${index} designing accessible applications`).join(
+	" ",
+);
+
+const renderHeader = async (locale: string, hasPicture: boolean) => {
+	const data = structuredClone(defaultResumeData);
+	data.basics.name = "Audit";
+	data.basics.headline = HEADLINE;
+	data.picture.hidden = !hasPicture;
+	data.picture.url = PICTURE;
+	data.picture.size = 100;
+	data.metadata.page.locale = locale;
+	data.metadata.page.marginX = 30;
+	data.metadata.typography.body.fontFamily = "Helvetica";
+	data.metadata.typography.heading.fontFamily = "Helvetica";
+	data.metadata.stylesheet = { mode: "semantic", source: { languageVersion: 1, text: "@version 1;" } };
+	data.metadata.layout.pages = [{ fullWidth: true, main: [], sidebar: [] }];
+	const element = createElement(ResumeDocument, { data, template: "onyx" }) as unknown as Parameters<
+		typeof renderToBuffer
+	>[0];
+	let bytes: Uint8Array = new Uint8Array();
+	await act(async () => {
+		bytes = new Uint8Array(await renderToBuffer(element));
+	});
+	const loadingTask = getDocument({ data: bytes, useSystemFonts: true });
+	try {
+		const document = await loadingTask.promise;
+		const page = await document.getPage(1);
+		const content = await page.getTextContent();
+		return content.items.filter(
+			(item): item is TextItem => "str" in item && item.str !== "Audit" && Boolean(item.str.trim()),
+		);
+	} finally {
+		await loadingTask.destroy();
+	}
+};
+
+describe("Onyx headline width (#3339)", () => {
+	it.each([
+		{ locale: "en-US", hasPicture: true },
+		{ locale: "ar-SA", hasPicture: true },
+		{ locale: "en-US", hasPicture: false },
+	])(
+		"keeps the complete headline within page margins ($locale, picture: $hasPicture)",
+		async ({ locale, hasPicture }) => {
+			const lines = await renderHeader(locale, hasPicture);
+			expect(
+				lines
+					.map((line) => line.str)
+					.join(" ")
+					.replace(/\s+/g, " "),
+			).toBe(HEADLINE);
+			for (const line of lines) {
+				expect(line.transform[4]).toBeGreaterThanOrEqual(29.9);
+				expect(line.transform[4] + line.width).toBeLessThanOrEqual(565.38);
+			}
+			if (locale === "en-US" && hasPicture) {
+				// The 100pt photo keeps its width, followed by the configured 4pt gap.
+				expect(lines[0]?.transform[4]).toBeCloseTo(134, 1);
+			}
+		},
+	);
+});
diff --git a/packages/pdf/src/templates/onyx/OnyxPage.tsx b/packages/pdf/src/templates/onyx/OnyxPage.tsx
index 18db0f696..df488d39d 100644
--- a/packages/pdf/src/templates/onyx/OnyxPage.tsx
+++ b/packages/pdf/src/templates/onyx/OnyxPage.tsx
@@ -165,6 +165,7 @@ const useOnyxTemplate = (): OnyxTemplate => {
 				paddingBottom: metrics.page.paddingVertical,
 			},
 			headerTitle: {
+				flex: 1,
 				rowGap: metrics.gapY(0.5),
 			},
 			headerIdentity: {