diff --git a/tests/FSharp.Compiler.ComponentTests/CompilerOptions/Fsc/ParserErrors.fs b/tests/FSharp.Compiler.ComponentTests/CompilerOptions/Fsc/ParserErrors.fs
new file mode 100644
index 00000000000..15d896680d5
--- /dev/null
+++ b/tests/FSharp.Compiler.ComponentTests/CompilerOptions/Fsc/ParserErrors.fs
@@ -0,0 +1,117 @@
+// Copyright (c) Microsoft Corporation.  All Rights Reserved.  See License.txt in the project root for license information.
+
+namespace CompilerOptions.Fsc
+
+open Xunit
+open FSharp.Test.Compiler
+
+/// Tests for compiler options parser error handling across many options
+module ParserErrors =
+
+    // =================================================================
+    // Missing argument — options that require a parameter (error 224)
+    // =================================================================
+
+    [<Theory>]
+    [<InlineData("--out")>]
+    [<InlineData("--doc")>]
+    [<InlineData("--keyfile")>]
+    [<InlineData("--platform")>]
+    [<InlineData("--win32icon")>]
+    [<InlineData("--win32res")>]
+    [<InlineData("--win32manifest")>]
+    [<InlineData("--resource")>]
+    [<InlineData("--linkresource")>]
+    [<InlineData("--baseaddress")>]
+    [<InlineData("--pdb")>]
+    [<InlineData("--lib")>]
+    [<InlineData("--codepage")>]
+    [<InlineData("--sourcelink")>]
+    [<InlineData("--subsystemversion")>]
+    [<InlineData("--checksumalgorithm")>]
+    [<InlineData("--define")>]
+    [<InlineData("--warn")>]
+    [<InlineData("--maxerrors")>]
+    let ``options requiring a parameter produce error 224 when missing`` (option: string) =
+        Fs """module M"""
+        |> withOptions [option]
+        |> compile
+        |> shouldFail
+        |> withErrorCode 224
+        |> withDiagnosticMessageMatches "Option requires parameter"
+        |> ignore
+
+    // =================================================================
+    // Invalid integer argument — options expecting int get a non-integer
+    // =================================================================
+
+    [<Theory>]
+    [<InlineData("--maxerrors:xyz")>]
+    [<InlineData("--codepage:abc")>]
+    let ``int options with non-integer argument produce error 241`` (option: string) =
+        Fs """module M"""
+        |> withOptions [option]
+        |> compile
+        |> shouldFail
+        |> withErrorCode 241
+        |> withDiagnosticMessageMatches "is not a valid integer argument"
+        |> ignore
+
+    // =================================================================
+    // Invalid warn level — out of valid range 0-5
+    // =================================================================
+
+    [<Fact>]
+    let ``warn with negative level produces error 1050`` () =
+        Fs """module M"""
+        |> withOptions ["--warn:-1"]
+        |> compile
+        |> shouldFail
+        |> withErrorCode 1050
+        |> withDiagnosticMessageMatches "Invalid warning level"
+        |> ignore
+
+    // =================================================================
+    // Invalid target value
+    // =================================================================
+
+    [<Fact>]
+    let ``target with unrecognized value produces error 1048`` () =
+        Fs """module M"""
+        |> withOptions ["--target:dll"]
+        |> compile
+        |> shouldFail
+        |> withErrorCode 1048
+        |> withDiagnosticMessageMatches "Unrecognized target"
+        |> ignore
+
+    // =================================================================
+    // Invalid checksum algorithm
+    // =================================================================
+
+    [<Fact>]
+    let ``checksumalgorithm with unsupported algorithm produces error 1065`` () =
+        Fs """module M"""
+        |> withOptions ["--checksumalgorithm:MD5"]
+        |> compile
+        |> shouldFail
+        |> withErrorCode 1065
+        |> withDiagnosticMessageMatches "Algorithm.*is not supported"
+        |> ignore
+
+    // =================================================================
+    // Unrecognized option (error 243)
+    // =================================================================
+
+    [<Theory>]
+    [<InlineData("--nonexistent")>]
+    [<InlineData("--Optimize")>]      // case-sensitive: --optimize (parsed as --optimize+) works, --Optimize does not
+    [<InlineData("---debug")>]
+    let ``unrecognized options produce error 243`` (option: string) =
+        Fs """module M"""
+        |> withOptions [option]
+        |> compile
+        |> shouldFail
+        |> withErrorCode 243
+        |> withDiagnosticMessageMatches "Unrecognized option"
+        |> ignore
diff --git a/tests/FSharp.Compiler.ComponentTests/CompilerOptions/Fsc/UncoveredOptions.fs b/tests/FSharp.Compiler.ComponentTests/CompilerOptions/Fsc/UncoveredOptions.fs
new file mode 100644
index 00000000000..dc0c6e0762f
--- /dev/null
+++ b/tests/FSharp.Compiler.ComponentTests/CompilerOptions/Fsc/UncoveredOptions.fs
@@ -0,0 +1,109 @@
+// Copyright (c) Microsoft Corporation.  All Rights Reserved.  See License.txt in the project root for license information.
+
+namespace CompilerOptions.Fsc
+
+open Xunit
+open FSharp.Test.Compiler
+
+/// Smoke tests for compiler options that have no dedicated test coverage
+module UncoveredOptions =
+
+    // =================================================================
+    // Switch options (+/-) — verify parser accepts both polarities
+    // =================================================================
+
+    [<Theory>]
+    [<InlineData("--realsig+")>]
+    [<InlineData("--realsig-")>]
+    [<InlineData("--compressmetadata+")>]
+    [<InlineData("--compressmetadata-")>]
+    [<InlineData("--checknulls+")>]
+    [<InlineData("--checknulls-")>]
+    [<InlineData("--strict-indentation+")>]
+    [<InlineData("--strict-indentation-")>]
+    [<InlineData("--quotations-debug+")>]
+    [<InlineData("--quotations-debug-")>]
+    [<InlineData("--tailcalls+")>]
+    [<InlineData("--tailcalls-")>]
+    [<InlineData("--deterministic+")>]
+    [<InlineData("--deterministic-")>]
+    let ``switch options are accepted by the parser`` (option: string) =
+        Fs """module M"""
+        |> withOptions [option]
+        |> ignoreWarnings
+        |> typecheck
+        |> shouldSucceed
+        |> ignore
+
+    // =================================================================
+    // Unit options (no argument) — verify parser accepts them
+    // =================================================================
+
+    [<Theory>]
+    [<InlineData("--nooptimizationdata")>]
+    [<InlineData("--nointerfacedata")>]
+    [<InlineData("--nocopyfsharpcore")>]
+    [<InlineData("--nowin32manifest")>]
+    [<InlineData("--allsigs")>]         // typecheck only — compile would write .fsi files
+    [<InlineData("--utf8output")>]
+    [<InlineData("--fullpaths")>]
+    let ``unit options are accepted by the parser`` (option: string) =
+        Fs """module M"""
+        |> withOptions [option]
+        |> ignoreWarnings
+        |> typecheck
+        |> shouldSucceed
+        |> ignore
+
+    // =================================================================
+    // String options with valid values — verify parser + compilation
+    // =================================================================
+
+    [<Theory>]
+    [<InlineData("SHA1")>]
+    [<InlineData("SHA256")>]
+    let ``checksumalgorithm with valid algorithm is accepted`` (algorithm: string) =
+        Fs """module M"""
+        |> withOptions [$"--checksumalgorithm:{algorithm}"]
+        |> compile
+        |> shouldSucceed
+        |> ignore
+
+    [<Theory>]
+    [<InlineData("--target:exe")>]
+    [<InlineData("--target:winexe")>]
+    [<InlineData("--target:library")>]
+    [<InlineData("--target:module")>]
+    let ``target with valid values is accepted`` (option: string) =
+        Fs """module M"""
+        |> withOptions [option]
+        |> ignoreWarnings
+        |> compile
+        |> shouldSucceed
+        |> ignore
+
+    // =================================================================
+    // Compilation modes
+    // =================================================================
+
+    [<Fact>]
+    let ``parseonly does not report type errors`` () =
+        Fs """let x: int = "not an int" """
+        |> asExe
+        |> withOptions ["--parseonly"]
+        |> ignoreWarnings
+        |> compile
+        |> shouldSucceed
+        |> ignore
+
+    // =================================================================
+    // Diagnostic format options
+    // =================================================================
+
+    [<Fact>]
+    let ``maxerrors with valid value is accepted`` () =
+        Fs """module M"""
+        |> withOptions ["--maxerrors:10"]
+        |> compile
+        |> shouldSucceed
+        |> ignore
diff --git a/tests/FSharp.Compiler.ComponentTests/FSharp.Compiler.ComponentTests.fsproj b/tests/FSharp.Compiler.ComponentTests/FSharp.Compiler.ComponentTests.fsproj
index f5d1048408e..b39533447d5 100644
--- a/tests/FSharp.Compiler.ComponentTests/FSharp.Compiler.ComponentTests.fsproj
+++ b/tests/FSharp.Compiler.ComponentTests/FSharp.Compiler.ComponentTests.fsproj
@@ -417,6 +417,8 @@
     <Compile Include="CompilerOptions\fsc\sourceFiles.fs" />
     <Compile Include="CompilerOptions\Fsc\FscCliTests.fs" />
     <Compile Include="CompilerOptions\Fsc\Removed.fs" />
+    <Compile Include="CompilerOptions\Fsc\ParserErrors.fs" />
+    <Compile Include="CompilerOptions\Fsc\UncoveredOptions.fs" />
     <Compile Include="CompilerOptions\Fsc\responsefile\responsefile.fs" />
     <Compile Include="CompilerOptions\fsc\standalone\standalone.fs" />
     <Compile Include="CompilerOptions\fsc\dumpAllCommandLineOptions\dumpAllCommandLineOptions.fs" />