diff --git a/api.go b/api.go
index ebac90f..fc5963d 100644
--- a/api.go
+++ b/api.go
@@ -52,6 +52,7 @@ type Engine struct {
 	swaggerContactEmail            string
 	swaggerLicenseName             string
 	swaggerLicenseURL              string
+	swaggerSecuritySchemes         map[string]any
 	swaggerExternalDocsDescription string
 	swaggerExternalDocsURL         string
 	pprofEnabled                   bool
diff --git a/options.go b/options.go
index bc2072a..3b99ee2 100644
--- a/options.go
+++ b/options.go
@@ -7,6 +7,7 @@ import (
 	"log/slog"
 	"net/http"
 	"slices"
+	"strings"
 	"time"
 
 	"github.com/99designs/gqlgen/graphql"
@@ -239,6 +240,37 @@ func WithSwaggerLicense(name, url string) Option {
 	}
 }
 
+// WithSwaggerSecuritySchemes merges custom OpenAPI security schemes into the
+// generated Swagger spec. Existing schemes are preserved unless the new map
+// defines the same key, in which case the later definition wins.
+//
+// Example:
+//
+//	api.WithSwaggerSecuritySchemes(map[string]any{
+//		"apiKeyAuth": map[string]any{
+//			"type": "apiKey",
+//			"in":   "header",
+//			"name": "X-API-Key",
+//		},
+//	})
+func WithSwaggerSecuritySchemes(schemes map[string]any) Option {
+	return func(e *Engine) {
+		if len(schemes) == 0 {
+			return
+		}
+		if e.swaggerSecuritySchemes == nil {
+			e.swaggerSecuritySchemes = make(map[string]any, len(schemes))
+		}
+		for name, scheme := range schemes {
+			name = strings.TrimSpace(name)
+			if name == "" || scheme == nil {
+				continue
+			}
+			e.swaggerSecuritySchemes[name] = scheme
+		}
+	}
+}
+
 // WithSwaggerExternalDocs adds top-level external documentation metadata to
 // the generated Swagger spec.
 // Empty URLs are ignored; the description is optional.
diff --git a/spec_builder_helper.go b/spec_builder_helper.go
index 5b3ee4f..463b768 100644
--- a/spec_builder_helper.go
+++ b/spec_builder_helper.go
@@ -29,6 +29,7 @@ func (e *Engine) OpenAPISpecBuilder() *SpecBuilder {
 		Servers:                 slices.Clone(e.swaggerServers),
 		LicenseName:             e.swaggerLicenseName,
 		LicenseURL:              e.swaggerLicenseURL,
+		SecuritySchemes:         cloneSecuritySchemes(e.swaggerSecuritySchemes),
 		ExternalDocsDescription: e.swaggerExternalDocsDescription,
 		ExternalDocsURL:         e.swaggerExternalDocsURL,
 	}
@@ -43,3 +44,15 @@ func (e *Engine) OpenAPISpecBuilder() *SpecBuilder {
 
 	return builder
 }
+
+func cloneSecuritySchemes(schemes map[string]any) map[string]any {
+	if len(schemes) == 0 {
+		return nil
+	}
+
+	out := make(map[string]any, len(schemes))
+	for name, scheme := range schemes {
+		out[name] = scheme
+	}
+	return out
+}
diff --git a/spec_builder_helper_test.go b/spec_builder_helper_test.go
index a2990be..e549889 100644
--- a/spec_builder_helper_test.go
+++ b/spec_builder_helper_test.go
@@ -23,6 +23,13 @@ func TestEngine_Good_OpenAPISpecBuilderCarriesEngineMetadata(t *testing.T) {
 		api.WithSwaggerContact("API Support", "https://example.com/support", "support@example.com"),
 		api.WithSwaggerServers("https://api.example.com", "/", "https://api.example.com"),
 		api.WithSwaggerLicense("EUPL-1.2", "https://eupl.eu/1.2/en/"),
+		api.WithSwaggerSecuritySchemes(map[string]any{
+			"apiKeyAuth": map[string]any{
+				"type": "apiKey",
+				"in":   "header",
+				"name": "X-API-Key",
+			},
+		}),
 		api.WithSwaggerExternalDocs("Developer guide", "https://example.com/docs"),
 		api.WithWSPath("/socket"),
 		api.WithWSHandler(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {})),
@@ -103,6 +110,24 @@ func TestEngine_Good_OpenAPISpecBuilderCarriesEngineMetadata(t *testing.T) {
 		t.Fatalf("expected termsOfService to be preserved, got %v", info["termsOfService"])
 	}
 
+	securitySchemes, ok := spec["components"].(map[string]any)["securitySchemes"].(map[string]any)
+	if !ok {
+		t.Fatal("expected securitySchemes metadata in generated spec")
+	}
+	apiKeyAuth, ok := securitySchemes["apiKeyAuth"].(map[string]any)
+	if !ok {
+		t.Fatal("expected apiKeyAuth security scheme in generated spec")
+	}
+	if apiKeyAuth["type"] != "apiKey" {
+		t.Fatalf("expected apiKeyAuth.type=apiKey, got %v", apiKeyAuth["type"])
+	}
+	if apiKeyAuth["in"] != "header" {
+		t.Fatalf("expected apiKeyAuth.in=header, got %v", apiKeyAuth["in"])
+	}
+	if apiKeyAuth["name"] != "X-API-Key" {
+		t.Fatalf("expected apiKeyAuth.name=X-API-Key, got %v", apiKeyAuth["name"])
+	}
+
 	externalDocs, ok := spec["externalDocs"].(map[string]any)
 	if !ok {
 		t.Fatal("expected externalDocs metadata in generated spec")