diff --git a/src/libraries/System.Runtime.InteropServices/gen/LibraryImportGenerator/Analyzers/ConvertToLibraryImportFixer.cs b/src/libraries/System.Runtime.InteropServices/gen/LibraryImportGenerator/Analyzers/ConvertToLibraryImportFixer.cs
index 14059607d30e51..14cbd2217559e1 100644
--- a/src/libraries/System.Runtime.InteropServices/gen/LibraryImportGenerator/Analyzers/ConvertToLibraryImportFixer.cs
+++ b/src/libraries/System.Runtime.InteropServices/gen/LibraryImportGenerator/Analyzers/ConvertToLibraryImportFixer.cs
@@ -30,6 +30,10 @@ public sealed class ConvertToLibraryImportFixer : CodeFixProvider
         public override FixAllProvider GetFixAllProvider() => CustomFixAllProvider.Instance;
 
         private const string ConvertToLibraryImportKey = "ConvertToLibraryImport,";
+        private static string AppendSuffix(string entryPoint, char? entryPointSuffix)
+            => entryPointSuffix.HasValue && entryPoint.LastOrDefault() == entryPointSuffix.Value
+                ? entryPoint
+                : entryPoint + entryPointSuffix;
         private static string AddSuffixKey(string baseKey, char suffix) => $"{baseKey}{suffix},";
         private static string AddUnsafeKey(string baseKey) => baseKey + "AddUnsafe,";
         private static string AddMayRequireAdditionalWorkKey(string baseKey) => baseKey + $"{ConvertToLibraryImportAnalyzer.MayRequireAdditionalWork},";
@@ -563,7 +567,7 @@ private static SyntaxNode GetLibraryImportAttribute(
 
             // Update attribute arguments for LibraryImport
             bool hasEntryPointAttributeArgument = false;
-            List<SyntaxNode> argumentsToAdd= new List<SyntaxNode>();
+            List<SyntaxNode> argumentsToAdd = new List<SyntaxNode>();
             List<SyntaxNode> argumentsToRemove = new List<SyntaxNode>();
             foreach (SyntaxNode argument in generator.GetAttributeArguments(libraryImportSyntax))
             {
@@ -647,17 +651,20 @@ private static SyntaxNode GetLibraryImportAttribute(
                                 argumentsToRemove.Add(attrArg);
                                 argumentsToAdd.Add(attrArg.WithExpression(
                                     SyntaxFactory.LiteralExpression(SyntaxKind.StringLiteralExpression,
-                                        SyntaxFactory.Literal(entryPoint + entryPointSuffix))));
+                                        SyntaxFactory.Literal(AppendSuffix(entryPoint, entryPointSuffix)))));
                             }
                         }
                         else
                         {
-                            argumentsToRemove.Add(attrArg);
-                            argumentsToAdd.Add(attrArg.WithExpression(
-                                SyntaxFactory.BinaryExpression(SyntaxKind.AddExpression,
-                                    attrArg.Expression,
-                                    SyntaxFactory.LiteralExpression(SyntaxKind.StringLiteralExpression,
-                                        SyntaxFactory.Literal(entryPointSuffix.ToString())))));
+                            if (dllImportData.EntryPointName!.LastOrDefault() != entryPointSuffix.Value)
+                            {
+                                argumentsToRemove.Add(attrArg);
+                                argumentsToAdd.Add(attrArg.WithExpression(
+                                    SyntaxFactory.BinaryExpression(SyntaxKind.AddExpression,
+                                        attrArg.Expression,
+                                        SyntaxFactory.LiteralExpression(SyntaxKind.StringLiteralExpression,
+                                            SyntaxFactory.Literal(entryPointSuffix.ToString())))));
+                            }
                         }
                     }
                 }
@@ -671,7 +678,7 @@ private static SyntaxNode GetLibraryImportAttribute(
             if (entryPointSuffix.HasValue && !hasEntryPointAttributeArgument)
             {
                 argumentsToAdd.Add(generator.AttributeArgument("EntryPoint",
-                    generator.LiteralExpression(methodName + entryPointSuffix.Value)));
+                    generator.LiteralExpression(AppendSuffix(methodName, entryPointSuffix.Value))));
             }
 
             libraryImportSyntax = generator.RemoveNodes(libraryImportSyntax, argumentsToRemove);
diff --git a/src/libraries/System.Runtime.InteropServices/tests/LibraryImportGenerator.UnitTests/ConvertToLibraryImportFixerTests.cs b/src/libraries/System.Runtime.InteropServices/tests/LibraryImportGenerator.UnitTests/ConvertToLibraryImportFixerTests.cs
index e9ef9e0fe7d585..e930c5d1493389 100644
--- a/src/libraries/System.Runtime.InteropServices/tests/LibraryImportGenerator.UnitTests/ConvertToLibraryImportFixerTests.cs
+++ b/src/libraries/System.Runtime.InteropServices/tests/LibraryImportGenerator.UnitTests/ConvertToLibraryImportFixerTests.cs
@@ -490,6 +490,222 @@ partial class Test
             await VerifyCodeFixAsync(source, fixedSourceWithASuffix, $"{ConvertToLibraryImportKey}A,");
         }
 
+        [InlineData(CharSet.Ansi, 'A')]
+        [InlineData(CharSet.Unicode, 'W')]
+        [Theory]
+        public async Task SuffixPresent_ExactSpelling_False_NoAutoCharSet_Provides_No_Suffix_And_Suffix_Fix(CharSet charSet, char suffix)
+        {
+            string source = $$"""
+                using System.Runtime.InteropServices;
+                partial class Test
+                {
+                    [DllImport("DoesNotExist", EntryPoint = "Entry{{suffix}}", ExactSpelling = false, CharSet = CharSet.{{charSet}})]
+                    public static extern void [|Method|]();
+                }
+                """;
+            string fixedSourceNoSuffix = $$"""
+                using System.Runtime.InteropServices;
+                partial class Test
+                {
+                    [LibraryImport("DoesNotExist", EntryPoint = "Entry{{suffix}}")]
+                    public static partial void {|CS8795:Method|}();
+                }
+                """;
+            await VerifyCodeFixAsync(source, fixedSourceNoSuffix, ConvertToLibraryImportKey);
+        }
+
+        [Fact]
+        public async Task SuffixWPresent_ExactSpelling_False_AutoCharSet_Provides_No_Suffix_And_Both_Suffix_Fixes()
+        {
+            string source = """
+
+                using System.Runtime.InteropServices;
+                partial class Test
+                {
+                    [DllImport("DoesNotExist", EntryPoint = "EntryW", ExactSpelling = false, CharSet = CharSet.Auto)]
+                    public static extern void [|Method|]();
+                }
+                """;
+            string fixedSourceNoSuffix = """
+
+                using System.Runtime.InteropServices;
+                partial class Test
+                {
+                    [LibraryImport("DoesNotExist", EntryPoint = "EntryW")]
+                    public static partial void {|CS8795:Method|}();
+                }
+                """;
+            await VerifyCodeFixAsync(source, fixedSourceNoSuffix, ConvertToLibraryImportKey);
+            string fixedSourceWithASuffix = """
+
+                using System.Runtime.InteropServices;
+                partial class Test
+                {
+                    [LibraryImport("DoesNotExist", EntryPoint = "EntryWA")]
+                    public static partial void {|CS8795:Method|}();
+                }
+                """;
+            await VerifyCodeFixAsync(source, fixedSourceWithASuffix, $"{ConvertToLibraryImportKey}A,");
+        }
+
+        [Fact]
+        public async Task SuffixAPresent_ExactSpelling_False_AutoCharSet_Provides_No_Suffix_And_Both_Suffix_Fixes()
+        {
+            string source = """
+
+                using System.Runtime.InteropServices;
+                partial class Test
+                {
+                    [DllImport("DoesNotExist", EntryPoint = "EntryA", ExactSpelling = false, CharSet = CharSet.Auto)]
+                    public static extern void [|Method|]();
+                }
+                """;
+            string fixedSourceNoSuffix = """
+
+                using System.Runtime.InteropServices;
+                partial class Test
+                {
+                    [LibraryImport("DoesNotExist", EntryPoint = "EntryA")]
+                    public static partial void {|CS8795:Method|}();
+                }
+                """;
+            await VerifyCodeFixAsync(source, fixedSourceNoSuffix, ConvertToLibraryImportKey);
+            string fixedSourceWithASuffix = """
+
+                using System.Runtime.InteropServices;
+                partial class Test
+                {
+                    [LibraryImport("DoesNotExist", EntryPoint = "EntryAW")]
+                    public static partial void {|CS8795:Method|}();
+                }
+                """;
+            await VerifyCodeFixAsync(source, fixedSourceWithASuffix, $"{ConvertToLibraryImportKey}W,");
+        }
+
+        [Fact]
+        public async Task SuffixPresent_ExactSpelling_False_ImplicitAnsiCharSet_Provides_No_Suffix_And_Suffix_Fix()
+        {
+            string source = """
+
+                using System.Runtime.InteropServices;
+                partial class Test
+                {
+                    [DllImport("DoesNotExist", EntryPoint = "EntryA", ExactSpelling = false)]
+                    public static extern void [|Method|]();
+                }
+                """;
+            string fixedSourceWithNoAdditionalSuffix = """
+
+                using System.Runtime.InteropServices;
+                partial class Test
+                {
+                    [LibraryImport("DoesNotExist", EntryPoint = "EntryA")]
+                    public static partial void {|CS8795:Method|}();
+                }
+                """;
+            await VerifyCodeFixAsync(source, fixedSourceWithNoAdditionalSuffix, $"{ConvertToLibraryImportKey}A,");
+        }
+
+        [Fact]
+        public async Task SuffixPresent_ExactSpelling_False_ConstantNonLiteralEntryPoint()
+        {
+            string source = """
+
+                using System.Runtime.InteropServices;
+                partial class Test
+                {
+                    private const string EntryPoint = "EntryA";
+                    [DllImport("DoesNotExist", EntryPoint = EntryPoint, CharSet = CharSet.Ansi, ExactSpelling = false)]
+                    public static extern void [|Method|]();
+                }
+                """;
+            string fixedSourceWithASuffix = """
+
+                using System.Runtime.InteropServices;
+                partial class Test
+                {
+                    private const string EntryPoint = "EntryA";
+                    [LibraryImport("DoesNotExist", EntryPoint = EntryPoint)]
+                    public static partial void {|CS8795:Method|}();
+                }
+                """;
+            await VerifyCodeFixAsync(source, fixedSourceWithASuffix, ConvertToLibraryImportKey);
+        }
+
+        [Fact]
+        public async Task SuffixPresent_Implicit_ExactSpelling_False_Offers_Suffix_Fix()
+        {
+            string source = """
+
+                using System.Runtime.InteropServices;
+                partial class Test
+                {
+                    [DllImport("DoesNotExist", CharSet = CharSet.Ansi)]
+                    public static extern void [|MethodA|]();
+                }
+                """;
+            string fixedSourceWithASuffix = """
+
+                using System.Runtime.InteropServices;
+                partial class Test
+                {
+                    [LibraryImport("DoesNotExist")]
+                    public static partial void {|CS8795:MethodA|}();
+                }
+                """;
+            await VerifyCodeFixAsync(source, fixedSourceWithASuffix, ConvertToLibraryImportKey);
+        }
+
+        [Fact]
+        public async Task SuffixPresent_ExactSpelling_False_NameOfEntryPoint()
+        {
+            string source = """
+
+                using System.Runtime.InteropServices;
+                partial class Test
+                {
+                    private const string FooA = "BarA";
+                    [DllImport("DoesNotExist", EntryPoint = nameof(FooA), CharSet = CharSet.Ansi, ExactSpelling = false)]
+                    public static extern void [|Method|]();
+                }
+                """;
+            string fixedSourceWithASuffix = """
+
+                using System.Runtime.InteropServices;
+                partial class Test
+                {
+                    private const string FooA = "BarA";
+                    [LibraryImport("DoesNotExist", EntryPoint = nameof(FooA))]
+                    public static partial void {|CS8795:Method|}();
+                }
+                """;
+            await VerifyCodeFixAsync(source, fixedSourceWithASuffix, ConvertToLibraryImportKey);
+        }
+
+        [Fact]
+        public async Task SuffixPresent_ExactSpelling_False_ImplicitEntryPointName()
+        {
+            string source = """
+
+                using System.Runtime.InteropServices;
+                partial class Test
+                {
+                    [DllImport("DoesNotExist", CharSet = CharSet.Ansi, ExactSpelling = false)]
+                    public static extern void [|MethodA|]();
+                }
+                """;
+            string fixedSourceWithASuffix = """
+
+                using System.Runtime.InteropServices;
+                partial class Test
+                {
+                    [LibraryImport("DoesNotExist")]
+                    public static partial void {|CS8795:MethodA|}();
+                }
+                """;
+            await VerifyCodeFixAsync(source, fixedSourceWithASuffix, ConvertToLibraryImportKey);
+        }
+
         [Fact]
         public async Task PreserveSigFalseSignatureModified()
         {