diff --git a/.changeset/giant-tips-laugh.md b/.changeset/giant-tips-laugh.md
new file mode 100644
index 000000000..a0da0df52
--- /dev/null
+++ b/.changeset/giant-tips-laugh.md
@@ -0,0 +1,5 @@
+---
+"@lightsparkdev/origin": patch
+---
+
+- Add initialWidth prop to Origin charts for SSR support
diff --git a/packages/origin/src/components/Chart/BarChart.tsx b/packages/origin/src/components/Chart/BarChart.tsx
index ab48c2c38..28f15b993 100644
--- a/packages/origin/src/components/Chart/BarChart.tsx
+++ b/packages/origin/src/components/Chart/BarChart.tsx
@@ -41,6 +41,11 @@ const clickIndexMeta = (index: number) => ({ index });
 
 export interface BarChartProps extends React.ComponentPropsWithoutRef<"div"> {
   data: ChartDatum[];
+  /**
+   * Pre-measurement width in pixels. Used as a fallback before
+   * ResizeObserver fires, enabling server-side rendering.
+   */
+  initialWidth?: number;
   dataKey?: string;
   series?: Series[];
   xKey?: string;
@@ -116,12 +121,13 @@ export const Bar = React.forwardRef<HTMLDivElement, BarChartProps>(function Bar(
     animate = true,
     getBarColor,
     orientation = "vertical",
+    initialWidth,
     className,
     ...props
   },
   ref,
 ) {
-  const { width, attachRef } = useResizeWidth();
+  const { width, attachRef } = useResizeWidth(initialWidth);
   const tooltipRef = React.useRef<HTMLDivElement>(null);
   const [activeIndex, setActiveIndex] = React.useState<number | null>(null);
 
diff --git a/packages/origin/src/components/Chart/Chart.stories.tsx b/packages/origin/src/components/Chart/Chart.stories.tsx
index 7e4eecfa0..a702886e7 100644
--- a/packages/origin/src/components/Chart/Chart.stories.tsx
+++ b/packages/origin/src/components/Chart/Chart.stories.tsx
@@ -44,6 +44,7 @@ export const Line: Story = {
     fill: false,
     fadeLeft: false,
     compareLabel: "",
+    initialWidth: undefined,
   },
   argTypes: {
     curve: { control: "radio", options: ["monotone", "linear"] },
@@ -228,6 +229,7 @@ export const BarGrouped: Story = {
     legend: false,
     loading: false,
     stacked: false,
+    initialWidth: undefined,
   },
   argTypes: {
     orientation: { control: "radio", options: ["vertical", "horizontal"] },
diff --git a/packages/origin/src/components/Chart/Chart.unit.test.ts b/packages/origin/src/components/Chart/Chart.unit.test.ts
index 8ee75d01c..24d768687 100644
--- a/packages/origin/src/components/Chart/Chart.unit.test.ts
+++ b/packages/origin/src/components/Chart/Chart.unit.test.ts
@@ -7,6 +7,8 @@
  */
 
 import { describe, it, expect, vi } from "vitest";
+import { renderHook, act } from "@testing-library/react";
+import { useResizeWidth } from "./hooks";
 import {
   linearScale,
   niceTicks,
@@ -871,3 +873,66 @@ describe("sankeyLinkPath", () => {
     expect(path).toContain("C");
   });
 });
+
+// ---------------------------------------------------------------------------
+// useResizeWidth
+// ---------------------------------------------------------------------------
+
+describe("useResizeWidth", () => {
+  it("returns 0 when called with no arguments", () => {
+    const { result } = renderHook(() => useResizeWidth());
+    expect(result.current.width).toBe(0);
+    expect(typeof result.current.attachRef).toBe("function");
+  });
+
+  it("returns initialWidth when no observer has fired", () => {
+    const { result } = renderHook(() => useResizeWidth(800));
+    expect(result.current.width).toBe(800);
+  });
+
+  it("returns initialWidth for various values", () => {
+    const { result: r1 } = renderHook(() => useResizeWidth(1024));
+    expect(r1.current.width).toBe(1024);
+
+    const { result: r2 } = renderHook(() => useResizeWidth(320));
+    expect(r2.current.width).toBe(320);
+  });
+
+  it("returns 0 when initialWidth is 0", () => {
+    const { result } = renderHook(() => useResizeWidth(0));
+    expect(result.current.width).toBe(0);
+  });
+
+  it("observer measurement takes over from initialWidth", () => {
+    let observerCallback: ResizeObserverCallback;
+    const mockObserver = {
+      observe: vi.fn(),
+      disconnect: vi.fn(),
+      unobserve: vi.fn(),
+    };
+    vi.stubGlobal(
+      "ResizeObserver",
+      vi.fn((cb: ResizeObserverCallback) => {
+        observerCallback = cb;
+        return mockObserver;
+      }),
+    );
+
+    const { result } = renderHook(() => useResizeWidth(800));
+    expect(result.current.width).toBe(800);
+
+    const fakeNode = { clientWidth: 0 } as HTMLDivElement;
+    act(() => result.current.attachRef(fakeNode));
+
+    act(() => {
+      observerCallback(
+        [{ contentRect: { width: 600 } }] as ResizeObserverEntry[],
+        {} as ResizeObserver,
+      );
+    });
+
+    expect(result.current.width).toBe(600);
+
+    vi.unstubAllGlobals();
+  });
+});
diff --git a/packages/origin/src/components/Chart/ComposedChart.tsx b/packages/origin/src/components/Chart/ComposedChart.tsx
index cea22ce25..f8805ef5d 100644
--- a/packages/origin/src/components/Chart/ComposedChart.tsx
+++ b/packages/origin/src/components/Chart/ComposedChart.tsx
@@ -59,6 +59,11 @@ type ResolvedComposedSeries = {
 export interface ComposedChartProps
   extends React.ComponentPropsWithoutRef<"div"> {
   data: ChartDatum[];
+  /**
+   * Pre-measurement width in pixels. Used as a fallback before
+   * ResizeObserver fires, enabling server-side rendering.
+   */
+  initialWidth?: number;
   series: ComposedSeries[];
   xKey?: string;
   height?: number;
@@ -130,12 +135,13 @@ export const Composed = React.forwardRef<HTMLDivElement, ComposedChartProps>(
       connectNulls = true,
       yDomain: yDomainProp,
       yDomainRight: yDomainRightProp,
+      initialWidth,
       className,
       ...props
     },
     ref,
   ) {
-    const { width, attachRef } = useResizeWidth();
+    const { width, attachRef } = useResizeWidth(initialWidth);
     const trackedClick = useTrackedCallback(
       analyticsName,
       "Chart.Composed",
diff --git a/packages/origin/src/components/Chart/FunnelChart.tsx b/packages/origin/src/components/Chart/FunnelChart.tsx
index ed2ced3ba..f3940fde5 100644
--- a/packages/origin/src/components/Chart/FunnelChart.tsx
+++ b/packages/origin/src/components/Chart/FunnelChart.tsx
@@ -19,6 +19,11 @@ export interface FunnelStage {
 export interface FunnelChartProps
   extends React.ComponentPropsWithoutRef<"div"> {
   data: FunnelStage[];
+  /**
+   * Pre-measurement width in pixels. Used as a fallback before
+   * ResizeObserver fires, enabling server-side rendering.
+   */
+  initialWidth?: number;
   formatValue?: (value: number) => string;
   formatRate?: (rate: number) => string;
   showRates?: boolean;
@@ -61,12 +66,13 @@ export const Funnel = React.forwardRef<HTMLDivElement, FunnelChartProps>(
       onClickDatum,
       onActiveChange,
       analyticsName,
+      initialWidth,
       className,
       ...props
     },
     ref,
   ) {
-    const { width, attachRef } = useResizeWidth();
+    const { width, attachRef } = useResizeWidth(initialWidth);
     const [activeIndex, setActiveIndex] = React.useState<number | null>(null);
 
     const onActiveChangeRef = React.useRef(onActiveChange);
diff --git a/packages/origin/src/components/Chart/LineChart.tsx b/packages/origin/src/components/Chart/LineChart.tsx
index 8351ba924..6902d5c50 100644
--- a/packages/origin/src/components/Chart/LineChart.tsx
+++ b/packages/origin/src/components/Chart/LineChart.tsx
@@ -47,6 +47,11 @@ export interface LineChartProps extends React.ComponentPropsWithoutRef<"div"> {
    * Array of data objects. Each object should contain keys matching `dataKey` or `series[].key`.
    */
   data: ChartDatum[];
+  /**
+   * Pre-measurement width in pixels. Used as a fallback before
+   * ResizeObserver fires, enabling server-side rendering.
+   */
+  initialWidth?: number;
   /** Data key for single-series charts. Pass this OR `series`, not both. */
   dataKey?: string;
   /** Series configuration for multi-series charts. */
@@ -150,12 +155,13 @@ export const Line = React.forwardRef<HTMLDivElement, LineChartProps>(
       formatXLabel,
       formatYLabel,
       connectNulls = true,
+      initialWidth,
       className,
       ...props
     },
     ref,
   ) {
-    const { width, attachRef } = useResizeWidth();
+    const { width, attachRef } = useResizeWidth(initialWidth);
     const trackedClick = useTrackedCallback(
       analyticsName,
       "Chart.Line",
diff --git a/packages/origin/src/components/Chart/PieChart.tsx b/packages/origin/src/components/Chart/PieChart.tsx
index 2edbdf984..48eb91762 100644
--- a/packages/origin/src/components/Chart/PieChart.tsx
+++ b/packages/origin/src/components/Chart/PieChart.tsx
@@ -17,6 +17,11 @@ export interface PieSegment {
 
 export interface PieChartProps extends React.ComponentPropsWithoutRef<"div"> {
   data: PieSegment[];
+  /**
+   * Pre-measurement width in pixels. Used as a fallback before
+   * ResizeObserver fires, enabling server-side rendering.
+   */
+  initialWidth?: number;
   height?: number;
   /** Inner radius ratio (0-1). Defaults to 0.65. */
   innerRadius?: number;
@@ -107,6 +112,7 @@ export const Pie = React.forwardRef<HTMLDivElement, PieChartProps>(function Pie(
     analyticsName,
     ariaLabel,
     formatValue,
+    initialWidth,
     className,
     ...props
   },
@@ -123,7 +129,7 @@ export const Pie = React.forwardRef<HTMLDivElement, PieChartProps>(function Pie(
     onClickDatum ? clickIndexMeta : undefined,
   );
 
-  const { width, attachRef } = useResizeWidth();
+  const { width, attachRef } = useResizeWidth(initialWidth);
   const [activeIndex, setActiveIndex] = React.useState<number | null>(null);
 
   const mergedRef = useMergedRef(ref, attachRef);
diff --git a/packages/origin/src/components/Chart/SankeyChart.tsx b/packages/origin/src/components/Chart/SankeyChart.tsx
index 90e500851..118886c77 100644
--- a/packages/origin/src/components/Chart/SankeyChart.tsx
+++ b/packages/origin/src/components/Chart/SankeyChart.tsx
@@ -23,6 +23,11 @@ export type { SankeyNode, SankeyLink } from "./sankeyLayout";
 export interface SankeyChartProps
   extends React.ComponentPropsWithoutRef<"div"> {
   data: SankeyData;
+  /**
+   * Pre-measurement width in pixels. Used as a fallback before
+   * ResizeObserver fires, enabling server-side rendering.
+   */
+  initialWidth?: number;
   nodeWidth?: number;
   nodePadding?: number;
   height?: number;
@@ -78,6 +83,7 @@ export const Sankey = React.forwardRef<HTMLDivElement, SankeyChartProps>(
       onClickNode,
       onClickLink,
       analyticsName,
+      initialWidth,
       className,
       ...props
     },
@@ -98,7 +104,7 @@ export const Sankey = React.forwardRef<HTMLDivElement, SankeyChartProps>(
       onClickLink ? sankeyLinkClickMeta : undefined,
     );
 
-    const { width, attachRef } = useResizeWidth();
+    const { width, attachRef } = useResizeWidth(initialWidth);
     const [active, setActive] = React.useState<ActiveElement>(null);
     const tooltipRef = React.useRef<HTMLDivElement>(null);
     const rootRef = React.useRef<HTMLDivElement | null>(null);
diff --git a/packages/origin/src/components/Chart/ScatterChart.tsx b/packages/origin/src/components/Chart/ScatterChart.tsx
index 29216dd55..97c2b5a18 100644
--- a/packages/origin/src/components/Chart/ScatterChart.tsx
+++ b/packages/origin/src/components/Chart/ScatterChart.tsx
@@ -39,6 +39,11 @@ export interface ScatterSeries {
 export interface ScatterChartProps
   extends React.ComponentPropsWithoutRef<"div"> {
   data: ScatterSeries[];
+  /**
+   * Pre-measurement width in pixels. Used as a fallback before
+   * ResizeObserver fires, enabling server-side rendering.
+   */
+  initialWidth?: number;
   height?: number;
   grid?: boolean;
   tooltip?: TooltipProp;
@@ -113,6 +118,7 @@ export const Scatter = React.forwardRef<HTMLDivElement, ScatterChartProps>(
       onActiveChange,
       analyticsName,
       interactive = true,
+      initialWidth,
       className,
       ...props
     },
@@ -126,7 +132,7 @@ export const Scatter = React.forwardRef<HTMLDivElement, ScatterChartProps>(
       onClickDatum ? scatterClickMeta : undefined,
     );
 
-    const { width, attachRef } = useResizeWidth();
+    const { width, attachRef } = useResizeWidth(initialWidth);
     const tooltipRef = React.useRef<HTMLDivElement>(null);
     const [activeDot, setActiveDot] = React.useState<ActiveDot | null>(null);
 
diff --git a/packages/origin/src/components/Chart/Sparkline.tsx b/packages/origin/src/components/Chart/Sparkline.tsx
index 2d5dbcc65..9e5237275 100644
--- a/packages/origin/src/components/Chart/Sparkline.tsx
+++ b/packages/origin/src/components/Chart/Sparkline.tsx
@@ -25,13 +25,14 @@ const SparklineBar = React.forwardRef<HTMLDivElement, SparklineProps>(
       dataKey,
       color,
       height = 40,
+      initialWidth,
       className,
       analyticsName: _analyticsName,
       ...props
     },
     ref,
   ) {
-    const { width, attachRef } = useResizeWidth();
+    const { width, attachRef } = useResizeWidth(initialWidth);
     const mergedRef = useMergedRef(ref, attachRef);
 
     const key = dataKey ?? "value";
diff --git a/packages/origin/src/components/Chart/StackedAreaChart.tsx b/packages/origin/src/components/Chart/StackedAreaChart.tsx
index 9090a9840..09e7f6d50 100644
--- a/packages/origin/src/components/Chart/StackedAreaChart.tsx
+++ b/packages/origin/src/components/Chart/StackedAreaChart.tsx
@@ -41,6 +41,11 @@ const clickIndexMeta = (index: number) => ({ index });
 export interface StackedAreaChartProps
   extends React.ComponentPropsWithoutRef<"div"> {
   data: ChartDatum[];
+  /**
+   * Pre-measurement width in pixels. Used as a fallback before
+   * ResizeObserver fires, enabling server-side rendering.
+   */
+  initialWidth?: number;
   series: [Series, Series, ...Series[]];
   xKey?: string;
   height?: number;
@@ -102,12 +107,13 @@ export const StackedArea = React.forwardRef<
     formatValue,
     formatXLabel,
     formatYLabel,
+    initialWidth,
     className,
     ...props
   },
   ref,
 ) {
-  const { width, attachRef } = useResizeWidth();
+  const { width, attachRef } = useResizeWidth(initialWidth);
   const trackedClick = useTrackedCallback(
     analyticsName,
     "Chart.StackedArea",
diff --git a/packages/origin/src/components/Chart/WaterfallChart.tsx b/packages/origin/src/components/Chart/WaterfallChart.tsx
index 9685adb81..13a3dba54 100644
--- a/packages/origin/src/components/Chart/WaterfallChart.tsx
+++ b/packages/origin/src/components/Chart/WaterfallChart.tsx
@@ -28,6 +28,11 @@ export interface WaterfallSegment {
 export interface WaterfallChartProps
   extends React.ComponentPropsWithoutRef<"div"> {
   data: WaterfallSegment[];
+  /**
+   * Pre-measurement width in pixels. Used as a fallback before
+   * ResizeObserver fires, enabling server-side rendering.
+   */
+  initialWidth?: number;
   formatValue?: (value: number) => string;
   formatYLabel?: (value: number) => string;
   showConnectors?: boolean;
@@ -86,12 +91,13 @@ export const Waterfall = React.forwardRef<HTMLDivElement, WaterfallChartProps>(
       onActiveChange,
       analyticsName,
       interactive: interactiveProp = true,
+      initialWidth,
       className,
       ...props
     },
     ref,
   ) {
-    const { width, attachRef } = useResizeWidth();
+    const { width, attachRef } = useResizeWidth(initialWidth);
     const tooltipRef = React.useRef<HTMLDivElement>(null);
     const [activeIndex, setActiveIndex] = React.useState<number | null>(null);
 
diff --git a/packages/origin/src/components/Chart/hooks.ts b/packages/origin/src/components/Chart/hooks.ts
index 2a4a12bf3..082b5da93 100644
--- a/packages/origin/src/components/Chart/hooks.ts
+++ b/packages/origin/src/components/Chart/hooks.ts
@@ -3,19 +3,19 @@ import type { CurveInterpolator } from "./utils";
 import type { ChartDatum, TooltipMode } from "./types";
 import { PAD_RIGHT, TOOLTIP_GAP } from "./types";
 
-export function useResizeWidth() {
-  const [width, setWidth] = React.useState(0);
+export function useResizeWidth(initialWidth?: number) {
+  const [measuredWidth, setMeasuredWidth] = React.useState<number | null>(null);
   const observerRef = React.useRef<ResizeObserver | null>(null);
 
   const attachRef = React.useCallback((node: HTMLDivElement | null) => {
     observerRef.current?.disconnect();
     if (node) {
       const observer = new ResizeObserver((entries) => {
-        for (const entry of entries) setWidth(entry.contentRect.width);
+        for (const entry of entries) setMeasuredWidth(entry.contentRect.width);
       });
       observer.observe(node);
       observerRef.current = observer;
-      setWidth(node.clientWidth);
+      setMeasuredWidth(node.clientWidth);
     }
   }, []);
 
@@ -23,6 +23,7 @@ export function useResizeWidth() {
     return () => observerRef.current?.disconnect();
   }, []);
 
+  const width = measuredWidth !== null ? measuredWidth : initialWidth ?? 0;
   return { width, attachRef };
 }