diff --git a/api/v1beta2/provider_types.go b/api/v1beta2/provider_types.go
index 178f733d4..b5fd94835 100644
--- a/api/v1beta2/provider_types.go
+++ b/api/v1beta2/provider_types.go
@@ -103,8 +103,11 @@ type ProviderSpec struct {
 	SecretRef *meta.LocalObjectReference `json:"secretRef,omitempty"`
 
 	// CertSecretRef specifies the Secret containing
-	// a PEM-encoded CA certificate (`caFile`).
+	// a PEM-encoded CA certificate (in the `ca.crt` key).
 	// +optional
+	//
+	// Note: Support for the `caFile` key has
+	// been deprecated.
 	CertSecretRef *meta.LocalObjectReference `json:"certSecretRef,omitempty"`
 
 	// Suspend tells the controller to suspend subsequent
diff --git a/config/crd/bases/notification.toolkit.fluxcd.io_providers.yaml b/config/crd/bases/notification.toolkit.fluxcd.io_providers.yaml
index a8b7ce2f1..88f1c99e6 100644
--- a/config/crd/bases/notification.toolkit.fluxcd.io_providers.yaml
+++ b/config/crd/bases/notification.toolkit.fluxcd.io_providers.yaml
@@ -236,8 +236,9 @@ spec:
                 maxLength: 2048
                 type: string
               certSecretRef:
-                description: CertSecretRef specifies the Secret containing a PEM-encoded
-                  CA certificate (`caFile`).
+                description: "CertSecretRef specifies the Secret containing a PEM-encoded
+                  CA certificate (in the `ca.crt` key). \n Note: Support for the `caFile`
+                  key has been deprecated."
                 properties:
                   name:
                     description: Name of the referent.
diff --git a/docs/api/v1beta2/notification.md b/docs/api/v1beta2/notification.md
index a47b9e719..59c5de580 100644
--- a/docs/api/v1beta2/notification.md
+++ b/docs/api/v1beta2/notification.md
@@ -372,7 +372,9 @@ github.com/fluxcd/pkg/apis/meta.LocalObjectReference
 <td>
 <em>(Optional)</em>
 <p>CertSecretRef specifies the Secret containing
-a PEM-encoded CA certificate (<code>caFile</code>).</p>
+a PEM-encoded CA certificate (in the <code>ca.crt</code> key).</p>
+<p>Note: Support for the <code>caFile</code> key has
+been deprecated.</p>
 </td>
 </tr>
 <tr>
@@ -964,7 +966,9 @@ github.com/fluxcd/pkg/apis/meta.LocalObjectReference
 <td>
 <em>(Optional)</em>
 <p>CertSecretRef specifies the Secret containing
-a PEM-encoded CA certificate (<code>caFile</code>).</p>
+a PEM-encoded CA certificate (in the <code>ca.crt</code> key).</p>
+<p>Note: Support for the <code>caFile</code> key has
+been deprecated.</p>
 </td>
 </tr>
 <tr>
diff --git a/docs/spec/v1beta2/providers.md b/docs/spec/v1beta2/providers.md
index 1f60fd213..644ce34e5 100644
--- a/docs/spec/v1beta2/providers.md
+++ b/docs/spec/v1beta2/providers.md
@@ -1095,11 +1095,12 @@ stringData:
 
 `.spec.certSecretRef` is an optional field to specify a name reference to a
 Secret in the same namespace as the Provider, containing the TLS CA certificate.
+The secret must be of type `kubernetes.io/tls` or `Opaque`.
 
 #### Example
 
 To enable notification-controller to communicate with a provider API over HTTPS
-using a self-signed TLS certificate, set the `caFile` like so:
+using a self-signed TLS certificate, set the `ca.crt` like so:
 
 ```yaml
 ---
@@ -1119,11 +1120,16 @@ kind: Secret
 metadata:
   name: my-ca-crt
   namespace: default
+type: kubernetes.io/tls # or Opaque
 stringData:
-  caFile: |
+  ca.crt: |
     <--- CA Key --->
 ```
 
+**Warning:** Support for the `caFile` key has been
+deprecated. If you have any Secrets using this key,
+the controller will log a deprecation warning.
+
 ### HTTP/S proxy
 
 `.spec.proxy` is an optional field to specify an HTTP/S proxy address.
diff --git a/internal/controller/alert_controller.go b/internal/controller/alert_controller.go
index d22e52e6d..0616f232a 100644
--- a/internal/controller/alert_controller.go
+++ b/internal/controller/alert_controller.go
@@ -178,7 +178,7 @@ func (r *AlertReconciler) isProviderReady(ctx context.Context, alert *apiv1beta2
 	providerName := types.NamespacedName{Namespace: alert.Namespace, Name: alert.Spec.ProviderRef.Name}
 	if err := r.Get(ctx, providerName, provider); err != nil {
 		// log not found errors since they get filtered out
-		ctrl.LoggerFrom(ctx).Error(err, "failed to get provider %s", providerName.String())
+		ctrl.LoggerFrom(ctx).Error(err, "failed to get provider", "provider", providerName.String())
 		return fmt.Errorf("failed to get provider '%s': %w", providerName.String(), err)
 	}
 
diff --git a/internal/controller/provider_controller.go b/internal/controller/provider_controller.go
index 8b07b052d..d1b753b44 100644
--- a/internal/controller/provider_controller.go
+++ b/internal/controller/provider_controller.go
@@ -190,6 +190,8 @@ func (r *ProviderReconciler) validateURLs(provider *apiv1beta2.Provider) error {
 }
 
 func (r *ProviderReconciler) validateCredentials(ctx context.Context, provider *apiv1beta2.Provider) error {
+	log := ctrl.LoggerFrom(ctx)
+
 	address := provider.Spec.Address
 	proxy := provider.Spec.Proxy
 	username := provider.Spec.Username
@@ -245,9 +247,19 @@ func (r *ProviderReconciler) validateCredentials(ctx context.Context, provider *
 			return fmt.Errorf("failed to read secret, error: %w", err)
 		}
 
-		caFile, ok := secret.Data["caFile"]
+		switch secret.Type {
+		case corev1.SecretTypeOpaque, corev1.SecretTypeTLS, "":
+		default:
+			return fmt.Errorf("cannot use secret '%s' to get TLS certificate: invalid secret type: '%s'", secret.Name, secret.Type)
+		}
+
+		caFile, ok := secret.Data["ca.crt"]
 		if !ok {
-			return fmt.Errorf("no caFile found in secret %s", provider.Spec.CertSecretRef.Name)
+			caFile, ok = secret.Data["caFile"]
+			if !ok {
+				return fmt.Errorf("no 'ca.crt' key found in secret '%s'", provider.Spec.CertSecretRef.Name)
+			}
+			log.Info("warning: specifying CA cert via 'caFile' is deprecated, please use 'ca.crt' instead")
 		}
 
 		certPool = x509.NewCertPool()
diff --git a/internal/controller/provider_controller_test.go b/internal/controller/provider_controller_test.go
index 585e52d07..652156acb 100644
--- a/internal/controller/provider_controller_test.go
+++ b/internal/controller/provider_controller_test.go
@@ -19,6 +19,7 @@ package controller
 import (
 	"context"
 	"fmt"
+	"os"
 	"testing"
 	"time"
 
@@ -237,3 +238,99 @@ func TestProviderReconciler_Reconcile(t *testing.T) {
 		}, timeout, time.Second).Should(BeTrue())
 	})
 }
+
+func TestProviderReconciler_Reconcile_cacert(t *testing.T) {
+	g := NewWithT(t)
+	namespaceName := "provider-" + randStringRunes(5)
+	secretName := "ca-secret-" + randStringRunes(5)
+
+	caCrt, err := os.ReadFile("./testdata/certs/ca.pem")
+	g.Expect(err).To(Not(HaveOccurred()))
+
+	g.Expect(createNamespace(namespaceName)).NotTo(HaveOccurred(), "failed to create test namespace")
+
+	providerKey := types.NamespacedName{
+		Name:      fmt.Sprintf("provider-%s", randStringRunes(5)),
+		Namespace: namespaceName,
+	}
+
+	provider := &apiv1beta2.Provider{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      providerKey.Name,
+			Namespace: providerKey.Namespace,
+		},
+		Spec: apiv1beta2.ProviderSpec{
+			Type:          "generic",
+			Address:       "https://webhook.internal",
+			CertSecretRef: &meta.LocalObjectReference{Name: secretName},
+		},
+	}
+	g.Expect(k8sClient.Create(context.Background(), provider)).To(Succeed())
+
+	certSecret := &corev1.Secret{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      secretName,
+			Namespace: providerKey.Namespace,
+		},
+		Data: map[string][]byte{
+			"caFile": []byte("invalid byte"),
+			"ca.crt": caCrt,
+		},
+	}
+	g.Expect(k8sClient.Create(context.Background(), certSecret)).To(Succeed())
+
+	r := &ProviderReconciler{
+		Client:        k8sClient,
+		EventRecorder: record.NewFakeRecorder(32),
+	}
+
+	t.Run("uses `ca.crt` instead of deprecated `caFile`", func(t *testing.T) {
+		g := NewWithT(t)
+		_, err = r.Reconcile(ctx, ctrl.Request{NamespacedName: client.ObjectKeyFromObject(provider)})
+		g.Expect(err).NotTo(HaveOccurred())
+	})
+
+	t.Run("works if only deprecated `caFile` is specified", func(t *testing.T) {
+		g := NewWithT(t)
+
+		clusterCertSecret := &corev1.Secret{}
+		g.Expect(k8sClient.Get(context.Background(), client.ObjectKeyFromObject(certSecret), clusterCertSecret)).To(Succeed())
+
+		patchHelper, err := patch.NewHelper(clusterCertSecret, k8sClient)
+		g.Expect(err).ToNot(HaveOccurred())
+		clusterCertSecret.Data = map[string][]byte{
+			"caFile": caCrt,
+		}
+		g.Expect(patchHelper.Patch(context.Background(), clusterCertSecret)).ToNot(HaveOccurred())
+
+		_, err = r.Reconcile(ctx, ctrl.Request{NamespacedName: client.ObjectKeyFromObject(provider)})
+		g.Expect(err).NotTo(HaveOccurred())
+	})
+
+	t.Run("returns error with certSecretRef of the wrong type", func(t *testing.T) {
+		g := NewWithT(t)
+
+		dockerSecret := &corev1.Secret{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      "docker-secret",
+				Namespace: providerKey.Namespace,
+			},
+			Type: corev1.DockerConfigJsonKey,
+		}
+		g.Expect(k8sClient.Create(context.Background(), dockerSecret)).To(Succeed())
+
+		clusterProvider := &apiv1beta2.Provider{}
+		g.Expect(k8sClient.Get(context.Background(), client.ObjectKeyFromObject(provider), clusterProvider)).To(Succeed())
+
+		patchHelper, err := patch.NewHelper(clusterProvider, k8sClient)
+		g.Expect(err).ToNot(HaveOccurred())
+		clusterProvider.Spec.CertSecretRef = &meta.LocalObjectReference{
+			Name: dockerSecret.Name,
+		}
+		g.Expect(patchHelper.Patch(context.Background(), clusterProvider)).ToNot(HaveOccurred())
+
+		_, err = r.Reconcile(ctx, ctrl.Request{NamespacedName: client.ObjectKeyFromObject(provider)})
+		g.Expect(err).To(HaveOccurred())
+		g.Expect(err.Error()).To(ContainSubstring("invalid secret type"))
+	})
+}
diff --git a/internal/controller/testdata/certs/Makefile b/internal/controller/testdata/certs/Makefile
new file mode 100644
index 000000000..2863849d4
--- /dev/null
+++ b/internal/controller/testdata/certs/Makefile
@@ -0,0 +1,20 @@
+# Copyright 2023 The Flux authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+all: ca-key.pem
+
+ca-key.pem: ca-csr.json
+	cfssl gencert -initca ca-csr.json | cfssljson -bare ca –
+ca.pem: ca-key.pem
+ca.csr: ca-key.pem
diff --git a/internal/controller/testdata/certs/ca-config.json b/internal/controller/testdata/certs/ca-config.json
new file mode 100644
index 000000000..a63e0dd23
--- /dev/null
+++ b/internal/controller/testdata/certs/ca-config.json
@@ -0,0 +1,13 @@
+{
+  "signing": {
+    "default": {
+      "expiry": "8760h"
+    },
+    "profiles": {
+      "kubernetes": {
+        "usages": ["signing", "key encipherment", "server auth", "client auth"],
+        "expiry": "8760h"
+      }
+    }
+  }
+}
diff --git a/internal/controller/testdata/certs/ca-csr.json b/internal/controller/testdata/certs/ca-csr.json
new file mode 100644
index 000000000..941277bb1
--- /dev/null
+++ b/internal/controller/testdata/certs/ca-csr.json
@@ -0,0 +1,9 @@
+{
+  "CN": "example.com CA",
+  "hosts": [
+    "127.0.0.1",
+    "localhost",
+    "example.com",
+    "www.example.com"
+  ]
+}
diff --git a/internal/controller/testdata/certs/ca-key.pem b/internal/controller/testdata/certs/ca-key.pem
new file mode 100644
index 000000000..a3b86348a
--- /dev/null
+++ b/internal/controller/testdata/certs/ca-key.pem
@@ -0,0 +1,5 @@
+-----BEGIN EC PRIVATE KEY-----
+MHcCAQEEIEY+R5pZqRQUvD2wrbL4HFl5IKFY84FEGHG5GHW1EojroAoGCCqGSM49
+AwEHoUQDQgAEDqdWaSYf2JT7L90ywnuhz2BS4zhy+v5juPLpBI0Indo8mHpOw9m+
+LCnMzN2WkcUYt+XLQwhaNNt0RBlfnXRzhw==
+-----END EC PRIVATE KEY-----
diff --git a/internal/controller/testdata/certs/ca.csr b/internal/controller/testdata/certs/ca.csr
new file mode 100644
index 000000000..ee4314138
--- /dev/null
+++ b/internal/controller/testdata/certs/ca.csr
@@ -0,0 +1,9 @@
+-----BEGIN CERTIFICATE REQUEST-----
+MIIBHzCBxgIBADAZMRcwFQYDVQQDEw5leGFtcGxlLmNvbSBDQTBZMBMGByqGSM49
+AgEGCCqGSM49AwEHA0IABA6nVmkmH9iU+y/dMsJ7oc9gUuM4cvr+Y7jy6QSNCJ3a
+PJh6TsPZviwpzMzdlpHFGLfly0MIWjTbdEQZX510c4egSzBJBgkqhkiG9w0BCQ4x
+PDA6MDgGA1UdEQQxMC+CCWxvY2FsaG9zdIILZXhhbXBsZS5jb22CD3d3dy5leGFt
+cGxlLmNvbYcEfwAAATAKBggqhkjOPQQDAgNIADBFAiEAl0UiOdxlEcuKrNAGh/Pv
+CFxMyX5shaeAsdGvq/gyXckCIFlTwheOJZZVRRQl9b0l5LUVeJyIH6mnvitFGyQ7
+NRk5
+-----END CERTIFICATE REQUEST-----
diff --git a/internal/controller/testdata/certs/ca.pem b/internal/controller/testdata/certs/ca.pem
new file mode 100644
index 000000000..1c5fbc3b8
--- /dev/null
+++ b/internal/controller/testdata/certs/ca.pem
@@ -0,0 +1,11 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
diff --git a/internal/server/event_handlers.go b/internal/server/event_handlers.go
index ffba6ce1b..b0a57227f 100644
--- a/internal/server/event_handlers.go
+++ b/internal/server/event_handlers.go
@@ -205,16 +205,28 @@ func (s *EventServer) handleEvent() func(w http.ResponseWriter, r *http.Request)
 					continue
 				}
 
-				caFile, ok := secret.Data["caFile"]
-				if !ok {
-					alertLogger.Error(err, "failed to read secret key caFile")
+				switch secret.Type {
+				case corev1.SecretTypeOpaque, corev1.SecretTypeTLS, "":
+				default:
+					alertLogger.Error(nil, "cannot use secret '%s' to get TLS certificate: invalid secret type: '%s'",
+						secret.Name, secret.Type)
 					continue
 				}
 
+				caFile, ok := secret.Data["ca.crt"]
+				if !ok {
+					caFile, ok = secret.Data["caFile"]
+					if !ok {
+						alertLogger.Error(nil, "no 'ca.crt' key found in secret '%s'", provider.Spec.CertSecretRef.Name)
+						continue
+					}
+					alertLogger.Info("warning: specifying CA cert via 'caFile' is deprecated, please use 'ca.crt' instead")
+				}
+
 				certPool = x509.NewCertPool()
 				ok = certPool.AppendCertsFromPEM(caFile)
 				if !ok {
-					alertLogger.Error(err, "could not append to cert pool")
+					alertLogger.Error(nil, "could not append to cert pool")
 					continue
 				}
 			}