diff --git a/internal/services/realtimeengine/ossrealtime/oss-realtime.go b/internal/services/realtimeengine/ossrealtime/oss-realtime.go
index 9316b1a7..bf65b0c3 100644
--- a/internal/services/realtimeengine/ossrealtime/oss-realtime.go
+++ b/internal/services/realtimeengine/ossrealtime/oss-realtime.go
@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"os"
+	"path/filepath"
 	"strings"
 
 	"github.com/Checkmarx/manifest-parser/pkg/parser"
@@ -74,6 +75,10 @@ func (o *OssRealtimeService) RunOssRealtimeScan(filePath, ignoredFilePath string
 		return nil, errorconstants.NewRealtimeEngineError("invalid file path").Error()
 	}
 
+	if err := validateSupportedManifestFile(filePath); err != nil {
+		return nil, err
+	}
+
 	pkgs, err := parseManifest(filePath)
 	if err != nil {
 		logger.PrintfIfVerbose("Failed to parse manifest file %s: %v", filePath, err)
@@ -174,6 +179,55 @@ func getPackageEntryFromPackageMap(
 	return &entry
 }
 
+// validateSupportedManifestFile checks if the manifest file format is supported by OSS realtime scanner.
+func validateSupportedManifestFile(filePath string) error {
+	manifestFileName := filepath.Base(filePath)
+	manifestFileExtension := filepath.Ext(manifestFileName)
+
+	// Check supported extensions
+	supportedExtensions := map[string]bool{
+		".csproj": true,
+		".sbt":    true,
+	}
+
+	// Check supported filenames
+	supportedFilenames := map[string]bool{
+		"pom.xml":                  true,
+		"package.json":             true,
+		"Directory.Packages.props": true,
+		"packages.config":          true,
+		"go.mod":                   true,
+		"build.gradle":             true,
+		"build.gradle.kts":         true,
+		"libs.versions.toml":       true,
+		"setup.cfg":                true,
+		"setup.py":                 true,
+		"pyproject.toml":           true,
+	}
+
+	// Check by extension
+	if supportedExtensions[manifestFileExtension] {
+		return nil
+	}
+
+	// Check by filename
+	if supportedFilenames[manifestFileName] {
+		return nil
+	}
+
+	// Special handling for .txt files (check prefix)
+	if manifestFileExtension == ".txt" {
+		if strings.HasPrefix(manifestFileName, "requirement") ||
+			strings.HasPrefix(manifestFileName, "packages") ||
+			strings.HasPrefix(manifestFileName, "constraint") {
+			return nil
+		}
+	}
+
+	// Manifest format is not supported
+	return errorconstants.NewRealtimeEngineError(fmt.Sprintf("OSS Realtime scanner doesn't currently support scanning '%s' file.", manifestFileName)).Error()
+}
+
 // parseManifest parses the manifest file and returns a list of packages.
 func parseManifest(filePath string) ([]models.Package, error) {
 	manifestParser := parser.ParsersFactory(filePath)
diff --git a/internal/services/realtimeengine/ossrealtime/oss-realtime_test.go b/internal/services/realtimeengine/ossrealtime/oss-realtime_test.go
index 3fc4e975..a3868cd5 100644
--- a/internal/services/realtimeengine/ossrealtime/oss-realtime_test.go
+++ b/internal/services/realtimeengine/ossrealtime/oss-realtime_test.go
@@ -388,3 +388,145 @@ func TestOssRealtimeScan_CsprojFile_ReturnsLocations(t *testing.T) {
 			"Location %d endIndex should be %d", i, expected.endIndex)
 	}
 }
+
+// Tests for validateSupportedManifestFile function
+func TestValidateSupportedManifestFile_ValidExtensions(t *testing.T) {
+	tests := []struct {
+		name     string
+		filePath string
+		isValid  bool
+	}{
+		{
+			name:     "CsprojExtension",
+			filePath: "project.csproj",
+			isValid:  true,
+		},
+		{
+			name:     "SbtExtension",
+			filePath: "build.sbt",
+			isValid:  true,
+		},
+		{
+			name:     "CsprojWithPath",
+			filePath: "/path/to/project.csproj",
+			isValid:  true,
+		},
+		{
+			name:     "SbtWithPath",
+			filePath: "src/build.sbt",
+			isValid:  true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := validateSupportedManifestFile(tt.filePath)
+			if tt.isValid {
+				assert.Nil(t, err, "Should accept %s file", tt.filePath)
+			} else {
+				assert.NotNil(t, err, "Should reject %s file", tt.filePath)
+			}
+		})
+	}
+}
+
+func TestValidateSupportedManifestFile_ValidFilenames(t *testing.T) {
+	tests := []struct {
+		name     string
+		filePath string
+	}{
+		{name: "PomXml", filePath: "pom.xml"},
+		{name: "PackageJson", filePath: "package.json"},
+		{name: "GoMod", filePath: "go.mod"},
+		{name: "BuildGradle", filePath: "build.gradle"},
+		{name: "BuildGradleKts", filePath: "build.gradle.kts"},
+		{name: "LibsVersionsToml", filePath: "libs.versions.toml"},
+		{name: "SetupCfg", filePath: "setup.cfg"},
+		{name: "SetupPy", filePath: "setup.py"},
+		{name: "PyprojectToml", filePath: "pyproject.toml"},
+		{name: "PackagesConfig", filePath: "packages.config"},
+		{name: "DirectoryPackagesProps", filePath: "Directory.Packages.props"},
+		{name: "PomXmlWithPath", filePath: "/path/to/pom.xml"},
+		{name: "PackageJsonWithPath", filePath: "src/package.json"},
+		{name: "GoModWithPath", filePath: "project/go.mod"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := validateSupportedManifestFile(tt.filePath)
+			assert.Nil(t, err, "Should accept %s file", tt.filePath)
+		})
+	}
+}
+
+func TestValidateSupportedManifestFile_ValidTxtFilesWithPrefixes(t *testing.T) {
+	tests := []struct {
+		name     string
+		filePath string
+	}{
+		{name: "RequirementsTxt", filePath: "requirements.txt"},
+		{name: "RequirementsDevTxt", filePath: "requirements-dev.txt"},
+		{name: "PackagesTxt", filePath: "packages.txt"},
+		{name: "ConstraintsTxt", filePath: "constraints.txt"},
+		{name: "RequirementsWithPath", filePath: "/path/to/requirements.txt"},
+		{name: "PackagesWithPath", filePath: "config/packages.txt"},
+		{name: "ConstraintsWithPath", filePath: "src/constraints.txt"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := validateSupportedManifestFile(tt.filePath)
+			assert.Nil(t, err, "Should accept %s file", tt.filePath)
+		})
+	}
+}
+
+func TestValidateSupportedManifestFile_InvalidTxtFilesWithoutPrefixes(t *testing.T) {
+	tests := []struct {
+		name     string
+		filePath string
+	}{
+		{name: "UnrelatedTxt", filePath: "readme.txt"},
+		{name: "DataTxt", filePath: "data.txt"},
+		{name: "ConfigTxt", filePath: "config.txt"},
+		{name: "InfoTxt", filePath: "info.txt"},
+		{name: "UnrelatedTxtWithPath", filePath: "/path/to/random.txt"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := validateSupportedManifestFile(tt.filePath)
+			assert.NotNil(t, err, "Should reject %s file (missing prefix)", tt.filePath)
+			// Verify error message indicates unsupported format
+			assert.Contains(t, err.Error(), "OSS Realtime scanner doesn't currently support scanning")
+		})
+	}
+}
+
+func TestValidateSupportedManifestFile_UnsupportedFormats(t *testing.T) {
+	tests := []struct {
+		name     string
+		filePath string
+	}{
+		{name: "RubyGemfile", filePath: "Gemfile"},
+		{name: "PHPComposer", filePath: "composer.json"},
+		{name: "RustCargo", filePath: "Cargo.toml"},
+		{name: "PythonPipfile", filePath: "Pipfile"},
+		{name: "JavaGradleProperties", filePath: "gradle.properties"},
+		{name: "NodeNpmLock", filePath: "package-lock.json"},
+		{name: "YarnLock", filePath: "yarn.lock"},
+		{name: "UnsupportedExtension", filePath: "manifest.xml"},
+		{name: "RandomFile", filePath: "random.txt"},
+		{name: "NoPyproject", filePath: "pyproject.yaml"},
+		{name: "PomWithDifferentName", filePath: "maven.xml"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := validateSupportedManifestFile(tt.filePath)
+			assert.NotNil(t, err, "Should reject %s file (unsupported format)", tt.filePath)
+			// Verify error message indicates unsupported format
+			assert.Contains(t, err.Error(), "OSS Realtime scanner doesn't currently support scanning")
+		})
+	}
+}
diff --git a/test/integration/oss-realtime_test.go b/test/integration/oss-realtime_test.go
index 0ccfcff5..cdd7971d 100644
--- a/test/integration/oss-realtime_test.go
+++ b/test/integration/oss-realtime_test.go
@@ -71,6 +71,20 @@ func TestOssRealtimeScan_PackageJsonFile_Success(t *testing.T) {
 	defer deleteCacheFile()
 }
 
+func TestOssRealtimeScan_UnsupportedManifestFormat_ReturnsError(t *testing.T) {
+	// Test with unsupported file format - should return error (using a .py file which is not a supported manifest)
+	args := []string{
+		"scan", "oss-realtime",
+		flag(commonParams.SourcesFlag), "data/python-vul-file.py",
+	}
+	err, _ := executeCommand(t, args...)
+	// Should fail with error
+	assert.NotNil(t, err, "Should fail with unsupported manifest format")
+	// Error message should indicate unsupported format
+	assert.Contains(t, err.Error(), "OSS Realtime scanner doesn't currently support scanning",
+		"Error message should indicate that format is not supported")
+}
+
 func validateCacheFileExist() bool {
 	cacheFilePath := os.TempDir() + "/oss-realtime-cache.json"
 	if _, err := os.Stat(cacheFilePath); os.IsNotExist(err) {