diff --git a/Tasks/UsePythonVersion/Tests/L0.ts b/Tasks/UsePythonVersion/Tests/L0.ts
index f31bf6497822..352975c577ca 100644
--- a/Tasks/UsePythonVersion/Tests/L0.ts
+++ b/Tasks/UsePythonVersion/Tests/L0.ts
@@ -28,6 +28,48 @@ describe('UsePythonVersion L0 Suite', function () {
         mockery.resetCache();
     })
 
+    it('converts Python prerelease versions to the semantic version format', function () {
+        mockery.registerMock('vsts-task-lib/task', mockTask);
+        mockery.registerMock('vsts-task-tool-lib/tool', {});
+        const uut = reload();
+
+        const testCases = [
+            {
+                versionSpec: '3.x',
+                expected: '3.x'
+            },
+            {
+                versionSpec: '3.3.6',
+                expected: '3.3.6'
+            },
+            {
+                versionSpec: '3.7.0b2',
+                expected: '3.7.0-b2'
+            },
+            {
+                versionSpec: '3.7.0rc',
+                expected: '3.7.0-rc'
+            },
+            {
+                versionSpec: '14.22.100a1000',
+                expected: '14.22.100-a1000'
+            },
+            {
+                versionSpec: '3.6.6b2 || >= 3.7.0rc',
+                expected: '3.6.6-b2 || >= 3.7.0-rc'
+            },
+            {
+                versionSpec: '3.7rc1', // invalid
+                expected: '3.7rc1'
+            },
+        ];
+
+        for (let tc of testCases) { // Node 5 can't handle destructuring assignment
+            const actual = uut.pythonVersionToSemantic(tc.versionSpec);
+            assert.strictEqual(actual, tc.expected);
+        }
+    })
+
     it('finds version in cache', async function () {
         let buildVariables: any = {};
         const mockBuildVariables = {
diff --git a/Tasks/UsePythonVersion/task.json b/Tasks/UsePythonVersion/task.json
index 15cca6118cb6..136a53277851 100644
--- a/Tasks/UsePythonVersion/task.json
+++ b/Tasks/UsePythonVersion/task.json
@@ -12,7 +12,7 @@
     "author": "Microsoft Corporation",
     "version": {
         "Major": 0,
-        "Minor": 132,
+        "Minor": 133,
         "Patch": 0
     },
     "preview": true,
diff --git a/Tasks/UsePythonVersion/task.loc.json b/Tasks/UsePythonVersion/task.loc.json
index caccb31bf317..39307723bbed 100644
--- a/Tasks/UsePythonVersion/task.loc.json
+++ b/Tasks/UsePythonVersion/task.loc.json
@@ -12,7 +12,7 @@
   "author": "Microsoft Corporation",
   "version": {
     "Major": 0,
-    "Minor": 132,
+    "Minor": 133,
     "Patch": 0
   },
   "preview": true,
diff --git a/Tasks/UsePythonVersion/usepythonversion.ts b/Tasks/UsePythonVersion/usepythonversion.ts
index 98173fd2d08a..d5d4834fa913 100644
--- a/Tasks/UsePythonVersion/usepythonversion.ts
+++ b/Tasks/UsePythonVersion/usepythonversion.ts
@@ -31,8 +31,19 @@ interface TaskParameters {
     readonly addToPath: boolean
 }
 
+export function pythonVersionToSemantic(versionSpec: string) {
+    const prereleaseVersion = /(\d+\.\d+\.\d+)([a|b|rc]\d*)/g;
+    return versionSpec.replace(prereleaseVersion, '$1-$2');
+}
+
 export async function usePythonVersion(parameters: TaskParameters, platform: Platform): Promise<void> {
-    const installDir: string | null = tool.findLocalTool('Python', parameters.versionSpec);
+    // Python's prelease versions look like `3.7.0b2`.
+    // This is the one part of Python versioning that does not look like semantic versioning, which specifies `3.7.0-b2`.
+    // If the version spec contains prerelease versions, we need to convert them to the semantic version equivalent
+    const semanticVersionSpec = pythonVersionToSemantic(parameters.versionSpec);
+    task.debug(`Semantic version spec of ${parameters.versionSpec} is ${semanticVersionSpec}`);
+
+    const installDir: string | null = tool.findLocalTool('Python', semanticVersionSpec);
     if (!installDir) {
         // Fail and list available versions
         throw new Error([