diff --git a/public/app/plugins/datasource/grafana-azure-monitor-datasource/components/MetricsQueryEditor/MetricNamespaceField.test.tsx b/public/app/plugins/datasource/grafana-azure-monitor-datasource/components/MetricsQueryEditor/MetricNamespaceField.test.tsx
new file mode 100644
index 00000000000..7fbd74de615
--- /dev/null
+++ b/public/app/plugins/datasource/grafana-azure-monitor-datasource/components/MetricsQueryEditor/MetricNamespaceField.test.tsx
@@ -0,0 +1,42 @@
+import React from 'react';
+import { render, screen } from '@testing-library/react';
+import MetricNamespaceField from './MetricNamespaceField';
+import createMockQuery from '../../__mocks__/query';
+import createMockDatasource from '../../__mocks__/datasource';
+import { AzureMonitorOption } from '../../types';
+
+const props = {
+  metricNamespaces: [],
+  query: createMockQuery(),
+  datasource: createMockDatasource(),
+  variableOptionGroup: { label: 'Templates', options: [] },
+  onQueryChange: jest.fn(),
+  setError: jest.fn(),
+};
+
+describe('Azure Monitor QueryEditor', () => {
+  it('should render the current value', async () => {
+    const metricNamespaces: AzureMonitorOption[] = [{ label: 'foo', value: 'foo' }];
+    const query = {
+      ...props.query,
+      azureMonitor: {
+        metricNamespace: 'foo',
+      },
+    };
+    render(<MetricNamespaceField {...props} metricNamespaces={metricNamespaces} query={query} />);
+    expect(screen.queryByText('foo')).toBeInTheDocument();
+  });
+
+  it('should render the current value even if it is not in the list of options', async () => {
+    const metricNamespaces: AzureMonitorOption[] = [{ label: 'foo', value: 'foo' }];
+    const query = {
+      ...props.query,
+      azureMonitor: {
+        metricNamespace: 'bar',
+      },
+    };
+    render(<MetricNamespaceField {...props} metricNamespaces={metricNamespaces} query={query} />);
+    expect(screen.queryByText('bar')).toBeInTheDocument();
+    expect(screen.queryByText('foo')).not.toBeInTheDocument();
+  });
+});
diff --git a/public/app/plugins/datasource/grafana-azure-monitor-datasource/components/MetricsQueryEditor/MetricNamespaceField.tsx b/public/app/plugins/datasource/grafana-azure-monitor-datasource/components/MetricsQueryEditor/MetricNamespaceField.tsx
index 99f2a365e8f..7d7992045c5 100644
--- a/public/app/plugins/datasource/grafana-azure-monitor-datasource/components/MetricsQueryEditor/MetricNamespaceField.tsx
+++ b/public/app/plugins/datasource/grafana-azure-monitor-datasource/components/MetricsQueryEditor/MetricNamespaceField.tsx
@@ -29,6 +29,11 @@ const MetricNamespaceField: React.FC<MetricNamespaceFieldProps> = ({
   );
 
   const options = useMemo(() => [...metricNamespaces, variableOptionGroup], [metricNamespaces, variableOptionGroup]);
+  const optionValues = metricNamespaces.map((m) => m.value).concat(variableOptionGroup.options.map((p) => p.value));
+  const value = query.azureMonitor?.metricNamespace;
+  if (value && !optionValues.includes(value)) {
+    options.push({ label: value, value });
+  }
 
   return (
     <Field label="Metric namespace">
diff --git a/public/app/plugins/datasource/grafana-azure-monitor-datasource/components/MetricsQueryEditor/dataHooks.test.ts b/public/app/plugins/datasource/grafana-azure-monitor-datasource/components/MetricsQueryEditor/dataHooks.test.ts
index 22a9af6cabb..e47ff20776f 100644
--- a/public/app/plugins/datasource/grafana-azure-monitor-datasource/components/MetricsQueryEditor/dataHooks.test.ts
+++ b/public/app/plugins/datasource/grafana-azure-monitor-datasource/components/MetricsQueryEditor/dataHooks.test.ts
@@ -5,6 +5,7 @@ import {
   updateSubscriptions,
   useAsyncState,
   useMetricNames,
+  useMetricNamespaces,
   useResourceGroups,
   useResourceNames,
   useResourceTypes,
@@ -93,7 +94,7 @@ interface TestScenario {
   invalidQueryPartial: AzureMetricQuery;
   templateVariableQueryPartial: AzureMetricQuery;
 
-  expectedClearedQueryPartial: AzureMetricQuery;
+  expectedClearedQueryPartial?: AzureMetricQuery;
   expectedOptions: AzureMonitorOption[];
 }
 
@@ -253,6 +254,47 @@ describe('AzureMonitor: metrics dataHooks', () => {
         metricName: undefined,
       },
     },
+
+    {
+      name: 'useMetricNamespaces',
+      hook: useMetricNamespaces,
+      emptyQueryPartial: {
+        resourceGroup: 'web-app-development',
+        metricDefinition: 'azure/vm',
+        resourceName: 'web-server',
+        metricNamespace: 'azure/vm',
+      },
+      validQueryPartial: {
+        resourceGroup: 'web-app-development',
+        metricDefinition: 'azure/vm',
+        resourceName: 'web-server',
+        metricNamespace: 'azure/vm',
+      },
+      invalidQueryPartial: {
+        resourceGroup: 'web-app-development',
+        metricDefinition: 'azure/vm',
+        resourceName: 'web-server',
+        metricNamespace: 'azure/vm',
+        metricName: 'invalid-metric',
+      },
+      templateVariableQueryPartial: {
+        resourceGroup: 'web-app-development',
+        metricDefinition: 'azure/vm',
+        resourceName: 'web-server',
+        metricNamespace: 'azure/vm',
+        metricName: '$variable',
+      },
+      expectedOptions: [
+        {
+          label: 'Compute Virtual Machine',
+          value: 'azure/vmc',
+        },
+        {
+          label: 'Database NS',
+          value: 'azure/dbns',
+        },
+      ],
+    },
   ];
 
   let datasource: MockedObjectDeep<Datasource>;
@@ -284,8 +326,11 @@ describe('AzureMonitor: metrics dataHooks', () => {
     datasource.getMetricNames = jest
       .fn()
       .mockResolvedValue([opt('Percentage CPU', 'percentage-cpu'), opt('Free memory', 'free-memory')]);
-  });
 
+    datasource.getMetricNamespaces = jest
+      .fn()
+      .mockResolvedValue([opt('Compute Virtual Machine', 'azure/vmc'), opt('Database NS', 'azure/dbns')]);
+  });
   describe.each(testTable)('scenario %#: $name', (scenario) => {
     it('returns values', async () => {
       const query = {
@@ -339,14 +384,18 @@ describe('AzureMonitor: metrics dataHooks', () => {
       const { waitForNextUpdate } = renderHook(() => scenario.hook(query, datasource, onChange, setError));
       await waitForNextUpdate(WAIT_OPTIONS);
 
-      expect(onChange).toHaveBeenCalledWith({
-        ...query,
-        azureMonitor: {
-          ...scenario.expectedClearedQueryPartial,
-          dimensionFilters: [],
-          timeGrain: '',
-        },
-      });
+      if (scenario.expectedClearedQueryPartial) {
+        expect(onChange).toHaveBeenCalledWith({
+          ...query,
+          azureMonitor: {
+            ...scenario.expectedClearedQueryPartial,
+            dimensionFilters: [],
+            timeGrain: '',
+          },
+        });
+      } else {
+        expect(onChange).not.toHaveBeenCalled();
+      }
     });
   });
 });
diff --git a/public/app/plugins/datasource/grafana-azure-monitor-datasource/components/MetricsQueryEditor/dataHooks.ts b/public/app/plugins/datasource/grafana-azure-monitor-datasource/components/MetricsQueryEditor/dataHooks.ts
index 0977360cec1..7a6d1c1458f 100644
--- a/public/app/plugins/datasource/grafana-azure-monitor-datasource/components/MetricsQueryEditor/dataHooks.ts
+++ b/public/app/plugins/datasource/grafana-azure-monitor-datasource/components/MetricsQueryEditor/dataHooks.ts
@@ -193,8 +193,6 @@ export const useMetricNamespaces: DataHook = (query, datasource, onChange, setEr
       // Do some cleanup of the query state if need be
       if (!metricNamespace && options.length) {
         onChange(setMetricNamespace(query, options[0].value));
-      } else if (options[0] && isInvalidOption(metricNamespace, options, datasource.getVariables())) {
-        onChange(setMetricNamespace(query, options[0].value));
       }
 
       return options;