diff --git a/change/@fluentui-react-charts-f07461ee-762b-4537-be4e-14c40f6113f8.json b/change/@fluentui-react-charts-f07461ee-762b-4537-be4e-14c40f6113f8.json
new file mode 100644
index 0000000000000..1b6dcfd1c6c89
--- /dev/null
+++ b/change/@fluentui-react-charts-f07461ee-762b-4537-be4e-14c40f6113f8.json
@@ -0,0 +1,7 @@
+{
+  "type": "patch",
+  "comment": "Marker size issue in scatter chart and line chart",
+  "packageName": "@fluentui/react-charts",
+  "email": "yushsingla@microsoft.com",
+  "dependentChangeType": "patch"
+}
diff --git a/packages/charts/react-charts/library/src/components/LineChart/LineChart.tsx b/packages/charts/react-charts/library/src/components/LineChart/LineChart.tsx
index e7139a619fb2c..9661c7c046ae9 100644
--- a/packages/charts/react-charts/library/src/components/LineChart/LineChart.tsx
+++ b/packages/charts/react-charts/library/src/components/LineChart/LineChart.tsx
@@ -519,6 +519,10 @@ export const LineChart: React.FunctionComponent<LineChartProps> = React.forwardR
 
     function _createLines(xElement: SVGElement, containerHeight: number): JSXElement[] {
       const lines: JSXElement[] = [];
+      // Collect all borders, lines, and points separately to ensure markers render on top of all lines
+      const allBorders: JSXElement[] = [];
+      const allLines: JSXElement[] = [];
+      const allPoints: JSXElement[] = [];
       if (isSelectedLegend) {
         _points = selectedLegendPoints;
       } else {
@@ -551,6 +555,7 @@ export const LineChart: React.FunctionComponent<LineChartProps> = React.forwardR
               secondaryYScaleType: props.secondaryYScaleType,
             })
           : 0;
+
         if (_points[i].data.length === 1) {
           const {
             x: x1,
@@ -576,7 +581,9 @@ export const LineChart: React.FunctionComponent<LineChartProps> = React.forwardR
                     key={circleId}
                     r={
                       currentMarkerSize
-                        ? (currentMarkerSize! * extraMaxPixels) / maxMarkerSize
+                        ? maxMarkerSize < extraMaxPixels
+                          ? currentMarkerSize
+                          : (currentMarkerSize * extraMaxPixels) / maxMarkerSize
                         : activePoint === circleId
                         ? 5.5
                         : 3.5
@@ -781,7 +788,9 @@ export const LineChart: React.FunctionComponent<LineChartProps> = React.forwardR
                     key={`${_circleId}_${i}_${k}_marker`}
                     r={
                       markerSize
-                        ? (markerSize! * extraMaxPixels * 0.3) / maxMarkerSize
+                        ? maxMarkerSize < extraMaxPixels
+                          ? markerSize
+                          : (markerSize * extraMaxPixels) / maxMarkerSize
                         : activePoint === _circleId
                         ? 5.5
                         : 3.5
@@ -846,7 +855,13 @@ export const LineChart: React.FunctionComponent<LineChartProps> = React.forwardR
                     <circle
                       id={circleId}
                       key={circleId}
-                      r={currentMarkerSize ? (currentMarkerSize! * extraMaxPixels) / maxMarkerSize : 4}
+                      r={
+                        currentMarkerSize
+                          ? maxMarkerSize < extraMaxPixels
+                            ? currentMarkerSize
+                            : (currentMarkerSize! * extraMaxPixels) / maxMarkerSize
+                          : 4
+                      }
                       cx={xPoint1}
                       cy={yPoint1}
                       tabIndex={isLegendSelected ? 0 : undefined}
@@ -999,7 +1014,13 @@ export const LineChart: React.FunctionComponent<LineChartProps> = React.forwardR
                         <circle
                           id={lastCircleId}
                           key={lastCircleId}
-                          r={currentMarkerSize ? (currentMarkerSize! * extraMaxPixels) / maxMarkerSize : 4}
+                          r={
+                            currentMarkerSize
+                              ? maxMarkerSize < extraMaxPixels
+                                ? currentMarkerSize
+                                : (currentMarkerSize * extraMaxPixels) / maxMarkerSize
+                              : 4
+                          }
                           cx={xPoint2}
                           cy={yPoint2}
                           tabIndex={isLegendSelected ? 0 : undefined}
@@ -1326,18 +1347,19 @@ export const LineChart: React.FunctionComponent<LineChartProps> = React.forwardR
           );
         }
 
-        lines.push(
-          <g
-            key={`line_${i}`}
-            role="region"
-            aria-label={`${legendVal}, line ${i + 1} of ${_points.length} with ${_points[i].data.length} data points.`}
-          >
-            {bordersForLine}
-            {linesForLine}
-            {pointsForLine}
-          </g>,
-        );
+        // Collect borders, lines, and points separately
+        allBorders.push(...bordersForLine);
+        allLines.push(...linesForLine);
+        allPoints.push(...pointsForLine);
       }
+
+      // Render all borders first, then all lines, then all points (markers)
+      // This ensures markers from all series appear on top of all lines
+      lines.push(
+        <g key="all-borders">{allBorders}</g>,
+        <g key="all-lines">{allLines}</g>,
+        <g key="all-points">{allPoints}</g>,
+      );
       return lines;
     }
 
diff --git a/packages/charts/react-charts/library/src/components/ScatterChart/ScatterChart.tsx b/packages/charts/react-charts/library/src/components/ScatterChart/ScatterChart.tsx
index 41f9dc4ac3561..82475151d6de3 100644
--- a/packages/charts/react-charts/library/src/components/ScatterChart/ScatterChart.tsx
+++ b/packages/charts/react-charts/library/src/components/ScatterChart/ScatterChart.tsx
@@ -421,7 +421,23 @@ export const ScatterChart: React.FunctionComponent<ScatterChartProps> = React.fo
 
         if (pointMarkerSize) {
           if (isContinuousXY && maxMarkerSize !== 0) {
-            circleRadius = (pointMarkerSize * extraMaxPixels) / maxMarkerSize;
+            /*
+              Example Scenario:
+              pointMarker = 100, extraMaxPixel=10,  max=100  (expected:10)
+              pointMarker=2, extraMaxPixel=100, max=2 (expected:2)
+              pointMarker=20, extraMaxPixel=25, max=30 (20- (scale_down_factor)*20 = 16.66) ::: (scale_down = 30--> 25, roughly -16.66%)
+            */
+            if (maxMarkerSize < extraMaxPixels) {
+              // if enough space is there, directly render the values, no need to scale it down or up
+              circleRadius = pointMarkerSize;
+            } else {
+              /*
+                markers are scaled down, based on available extra space
+                maxMarkerSize --> reduced to --> extraMaxPixels
+                other markers scaled down respectively
+              */
+              circleRadius = (pointMarkerSize / maxMarkerSize) * extraMaxPixels;
+            }
           } else if (!isContinuousXY && maxMarkerSize !== minMarkerSize) {
             circleRadius =
               minPixel + ((pointMarkerSize - minMarkerSize) / (maxMarkerSize - minMarkerSize)) * (maxPixel - minPixel);