diff --git a/cmd/osv-scanner/__snapshots__/main_test.snap b/cmd/osv-scanner/__snapshots__/main_test.snap
index 753a78f426..37c088facd 100755
--- a/cmd/osv-scanner/__snapshots__/main_test.snap
+++ b/cmd/osv-scanner/__snapshots__/main_test.snap
@@ -401,6 +401,16 @@ Ignored invalid config file at: <rootdir>/fixtures/config-invalid/osv-scanner.to
 
 ---
 
+[TestRun/config_files_cannot_have_unknown_keys - 1]
+
+---
+
+[TestRun/config_files_cannot_have_unknown_keys - 2]
+Failed to read config file: unknown keys in config file: RustVersionOverride, PackageOverrides.skip, PackageOverrides.license.skip
+unknown keys in config file: RustVersionOverride, PackageOverrides.skip, PackageOverrides.license.skip
+
+---
+
 [TestRun/cyclonedx_1.4_output - 1]
 {
   "$schema": "http://cyclonedx.org/schema/bom-1.4.schema.json",
diff --git a/cmd/osv-scanner/fixtures/osv-scanner-unknown-config.toml b/cmd/osv-scanner/fixtures/osv-scanner-unknown-config.toml
new file mode 100644
index 0000000000..9fa347cbf4
--- /dev/null
+++ b/cmd/osv-scanner/fixtures/osv-scanner-unknown-config.toml
@@ -0,0 +1,24 @@
+RustVersionOverride = "1.2.3"
+
+[[PackageOverrides]]
+ecosystem = "npm"
+skip = true
+license.override = ["0BSD"]
+
+[[PackageOverrides]]
+ecosystem = "Packagist"
+license.override = ["0BSD"]
+
+[[PackageOverrides]]
+ecosystem = "Alpine"
+Name = "musl"
+license.override = ["UNKNOWN"]
+
+[[PackageOverrides]]
+ecosystem = "Alpine"
+name = "musl-utils"
+license.skip = true
+
+[[IgnoredVulns]]
+id = "GO-2022-0274"
+ignoreuntil = 2020-01-01
diff --git a/cmd/osv-scanner/main_test.go b/cmd/osv-scanner/main_test.go
index f27e8c7051..62e2f1f864 100644
--- a/cmd/osv-scanner/main_test.go
+++ b/cmd/osv-scanner/main_test.go
@@ -335,6 +335,12 @@ func TestRun(t *testing.T) {
 			args: []string{"", "--verbosity", "verbose", "./fixtures/config-invalid"},
 			exit: 127,
 		},
+		// config file with unknown keys
+		{
+			name: "config files cannot have unknown keys",
+			args: []string{"", "--config=./fixtures/osv-scanner-unknown-config.toml", "./fixtures/locks-many"},
+			exit: 127,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
diff --git a/pkg/config/config.go b/pkg/config/config.go
index 9eb2653d02..388a4fcac8 100644
--- a/pkg/config/config.go
+++ b/pkg/config/config.go
@@ -6,6 +6,7 @@ import (
 	"os"
 	"path/filepath"
 	"slices"
+	"strings"
 	"time"
 
 	"github.com/BurntSushi/toml"
@@ -213,8 +214,20 @@ func normalizeConfigLoadPath(target string) (string, error) {
 // returning the Config object if successful or otherwise the error
 func tryLoadConfig(configPath string) (Config, error) {
 	config := Config{}
-	_, err := toml.DecodeFile(configPath, &config)
+	m, err := toml.DecodeFile(configPath, &config)
 	if err == nil {
+		unknownKeys := m.Undecoded()
+
+		if len(unknownKeys) > 0 {
+			keys := make([]string, 0, len(unknownKeys))
+
+			for _, key := range unknownKeys {
+				keys = append(keys, key.String())
+			}
+
+			return Config{}, fmt.Errorf("unknown keys in config file: %s", strings.Join(keys, ", "))
+		}
+
 		config.LoadPath = configPath
 	}
 
diff --git a/pkg/config/config_internal_test.go b/pkg/config/config_internal_test.go
index f1bb102278..23ba805436 100644
--- a/pkg/config/config_internal_test.go
+++ b/pkg/config/config_internal_test.go
@@ -1,6 +1,7 @@
 package config
 
 import (
+	"fmt"
 	"reflect"
 	"strings"
 	"testing"
@@ -183,6 +184,62 @@ func Test_tryLoadConfig(t *testing.T) {
 	}
 }
 
+func TestTryLoadConfig_UnknownKeys(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		configPath string
+		unknownMsg string
+	}{
+		{
+			configPath: "./fixtures/unknown-key-1.toml",
+			unknownMsg: "IgnoredVulns.ignoreUntilTime",
+		},
+		{
+			configPath: "./fixtures/unknown-key-2.toml",
+			unknownMsg: "IgnoredVulns.ignoreUntiI",
+		},
+		{
+			configPath: "./fixtures/unknown-key-3.toml",
+			unknownMsg: "IgnoredVulns.reasoning",
+		},
+		{
+			configPath: "./fixtures/unknown-key-4.toml",
+			unknownMsg: "PackageOverrides.skip",
+		},
+		{
+			configPath: "./fixtures/unknown-key-5.toml",
+			unknownMsg: "PackageOverrides.license.skip",
+		},
+		{
+			configPath: "./fixtures/unknown-key-6.toml",
+			unknownMsg: "RustVersionOverride",
+		},
+		{
+			configPath: "./fixtures/unknown-key-7.toml",
+			unknownMsg: "RustVersionOverride, PackageOverrides.skip",
+		},
+	}
+
+	for _, testData := range tests {
+		c, err := tryLoadConfig(testData.configPath)
+
+		// we should always be returning an empty config on error
+		if diff := cmp.Diff(Config{}, c); diff != "" {
+			t.Errorf("tryLoadConfig() mismatch (-want +got):\n%s", diff)
+		}
+		if err == nil {
+			t.Fatal("tryLoadConfig() did not return an error")
+		}
+
+		wantMsg := fmt.Sprintf("unknown keys in config file: %v", testData.unknownMsg)
+
+		if err.Error() != wantMsg {
+			t.Errorf("tryLoadConfig() error = '%v', want '%s'", err, wantMsg)
+		}
+	}
+}
+
 func TestConfig_ShouldIgnore(t *testing.T) {
 	t.Parallel()
 
diff --git a/pkg/config/fixtures/unknown-key-1.toml b/pkg/config/fixtures/unknown-key-1.toml
new file mode 100644
index 0000000000..2c8538325b
--- /dev/null
+++ b/pkg/config/fixtures/unknown-key-1.toml
@@ -0,0 +1,4 @@
+[[IgnoredVulns]]
+id = "GHSA-jgvc-jfgh-rjvv"
+ignoreUntilTime = 2024-08-02 # whoops, should be "ignoreUntil"
+reason = "..."
diff --git a/pkg/config/fixtures/unknown-key-2.toml b/pkg/config/fixtures/unknown-key-2.toml
new file mode 100644
index 0000000000..7b6d964f43
--- /dev/null
+++ b/pkg/config/fixtures/unknown-key-2.toml
@@ -0,0 +1,4 @@
+[[IgnoredVulns]]
+id = "GHSA-jgvc-jfgh-rjvv"
+ignoreUntiI = 2024-08-02 # whoops, should be "ignoreUntil"
+reason = "..."
diff --git a/pkg/config/fixtures/unknown-key-3.toml b/pkg/config/fixtures/unknown-key-3.toml
new file mode 100644
index 0000000000..bce7ed9a19
--- /dev/null
+++ b/pkg/config/fixtures/unknown-key-3.toml
@@ -0,0 +1,4 @@
+[[IgnoredVulns]]
+id = "GHSA-jgvc-jfgh-rjvv"
+ignoreUntil = 2024-08-02
+reasoning = "..." # whoops, should be "reason"
diff --git a/pkg/config/fixtures/unknown-key-4.toml b/pkg/config/fixtures/unknown-key-4.toml
new file mode 100644
index 0000000000..f508c89dd1
--- /dev/null
+++ b/pkg/config/fixtures/unknown-key-4.toml
@@ -0,0 +1,4 @@
+[[PackageOverrides]]
+ecosystem = "npm"
+skip = true # whoops, should be "ignore"
+license.override = ["0BSD"]
diff --git a/pkg/config/fixtures/unknown-key-5.toml b/pkg/config/fixtures/unknown-key-5.toml
new file mode 100644
index 0000000000..d1d832aed0
--- /dev/null
+++ b/pkg/config/fixtures/unknown-key-5.toml
@@ -0,0 +1,3 @@
+[[PackageOverrides]]
+ecosystem = "npm"
+license.skip = false # whoops, should be "license.ignore"
diff --git a/pkg/config/fixtures/unknown-key-6.toml b/pkg/config/fixtures/unknown-key-6.toml
new file mode 100644
index 0000000000..80f0b87eee
--- /dev/null
+++ b/pkg/config/fixtures/unknown-key-6.toml
@@ -0,0 +1 @@
+RustVersionOverride = "1.2.3" # whoops, not supported
diff --git a/pkg/config/fixtures/unknown-key-7.toml b/pkg/config/fixtures/unknown-key-7.toml
new file mode 100644
index 0000000000..044156ccec
--- /dev/null
+++ b/pkg/config/fixtures/unknown-key-7.toml
@@ -0,0 +1,5 @@
+RustVersionOverride = "1.2.3" # whoops, not supported
+
+[[PackageOverrides]]
+ecosystem = "npm"
+skip = true # whoops, should be "ignore"