diff --git a/internal/pkg/aws/ssm/errors.go b/internal/pkg/aws/ssm/errors.go
index 08689648ea5..0d8928ee4d7 100644
--- a/internal/pkg/aws/ssm/errors.go
+++ b/internal/pkg/aws/ssm/errors.go
@@ -13,3 +13,17 @@ type ErrParameterAlreadyExists struct {
 func (e *ErrParameterAlreadyExists) Error() string {
 	return fmt.Sprintf("parameter %s already exists", e.name)
 }
+
+// ErrParameterNotFound occurs when the parameter with name does not exist.
+type ErrParameterNotFound struct {
+	name      string
+	parentErr error
+}
+
+func (e *ErrParameterNotFound) Error() string {
+	return fmt.Sprintf("parameter %s does not exist", e.name)
+}
+
+func (e *ErrParameterNotFound) Unwrap() error {
+	return e.parentErr
+}
diff --git a/internal/pkg/aws/ssm/ssm.go b/internal/pkg/aws/ssm/ssm.go
index ddc00996c62..b1bdbf755bc 100644
--- a/internal/pkg/aws/ssm/ssm.go
+++ b/internal/pkg/aws/ssm/ssm.go
@@ -72,6 +72,9 @@ func (s *SSM) GetSecretValue(ctx context.Context, name string) (string, error) {
 		WithDecryption: aws.Bool(true),
 	})
 	if err != nil {
+		if aerr, ok := err.(awserr.Error); ok && aerr.Code() == ssm.ErrCodeParameterNotFound {
+			return "", &ErrParameterNotFound{name: name, parentErr: err}
+		}
 		return "", fmt.Errorf("get parameter %q from SSM: %w", name, err)
 	}
 	return aws.StringValue(resp.Parameter.Value), nil
diff --git a/internal/pkg/aws/ssm/ssm_test.go b/internal/pkg/aws/ssm/ssm_test.go
index 6c032ac6b27..31d7bf0e762 100644
--- a/internal/pkg/aws/ssm/ssm_test.go
+++ b/internal/pkg/aws/ssm/ssm_test.go
@@ -377,6 +377,16 @@ func TestSSM_GetSecretValue(t *testing.T) {
 			},
 			wantError: `get parameter "asdf" from SSM: some error`,
 		},
+		"parameter not found": {
+			secretName: "missing",
+			setupMock: func(m *mocks.Mockapi) {
+				m.EXPECT().GetParameterWithContext(gomock.Any(), &ssm.GetParameterInput{
+					Name:           aws.String("missing"),
+					WithDecryption: aws.Bool(true),
+				}).Return(nil, awserr.New(ssm.ErrCodeParameterNotFound, "parameter not found", nil))
+			},
+			wantError: `parameter missing does not exist`,
+		},
 		"success": {
 			secretName: "asdf",
 			setupMock: func(m *mocks.Mockapi) {
diff --git a/internal/pkg/cli/svc_deploy.go b/internal/pkg/cli/svc_deploy.go
index 41eebaba21d..161e5e82527 100644
--- a/internal/pkg/cli/svc_deploy.go
+++ b/internal/pkg/cli/svc_deploy.go
@@ -4,6 +4,7 @@
 package cli
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"io"
@@ -13,10 +14,12 @@ import (
 
 	"github.com/aws/aws-sdk-go/aws"
 	"github.com/aws/aws-sdk-go/aws/session"
-	"github.com/aws/aws-sdk-go/service/ssm"
+	sdkssm "github.com/aws/aws-sdk-go/service/ssm"
 	"github.com/aws/copilot-cli/internal/pkg/aws/cloudformation"
 	awscfn "github.com/aws/copilot-cli/internal/pkg/aws/cloudformation"
 	"github.com/aws/copilot-cli/internal/pkg/aws/identity"
+	awssecretsmanager "github.com/aws/copilot-cli/internal/pkg/aws/secretsmanager"
+	awsssm "github.com/aws/copilot-cli/internal/pkg/aws/ssm"
 	"github.com/aws/copilot-cli/internal/pkg/aws/tags"
 	deploycfn "github.com/aws/copilot-cli/internal/pkg/deploy/cloudformation"
 	"github.com/aws/copilot-cli/internal/pkg/deploy/cloudformation/stack"
@@ -71,6 +74,8 @@ type deploySvcOpts struct {
 	newSvcDeployer       func() (workloadDeployer, error)
 	svcVersionGetter     versionGetter
 	envFeaturesDescriber versionCompatibilityChecker
+	ssmParamGetter       secretGetter
+	secretsmanager       secretDeleter
 	diffWriter           io.Writer
 
 	spinner        progress
@@ -105,7 +110,7 @@ func newSvcDeployOpts(vars deployWkldVars) (*deploySvcOpts, error) {
 		return nil, err
 	}
 
-	store := config.NewSSMStore(identity.New(defaultSession), ssm.New(defaultSession), aws.StringValue(defaultSession.Config.Region))
+	store := config.NewSSMStore(identity.New(defaultSession), sdkssm.New(defaultSession), aws.StringValue(defaultSession.Config.Region))
 	prompter := prompt.New()
 
 	opts := &deploySvcOpts{
@@ -238,6 +243,7 @@ func (o *deploySvcOpts) Execute() error {
 	if err := validateWorkloadManifestCompatibilityWithEnv(o.ws, o.envFeaturesDescriber, mft, o.envName); err != nil {
 		return err
 	}
+	o.warnMissingSecrets(context.Background(), mft.Manifest())
 	deployer, err := o.newSvcDeployer()
 	if err != nil {
 		return err
@@ -451,6 +457,8 @@ func (o *deploySvcOpts) configureClients() error {
 		return err
 	}
 	o.envSess = envSess
+	o.ssmParamGetter = awsssm.New(envSess)
+	o.secretsmanager = awssecretsmanager.New(envSess)
 
 	// client to retrieve caller identity.
 	caller, err := identity.New(defaultSess).Get()
diff --git a/internal/pkg/cli/svc_deploy_secrets.go b/internal/pkg/cli/svc_deploy_secrets.go
new file mode 100644
index 00000000000..3aa06f7f904
--- /dev/null
+++ b/internal/pkg/cli/svc_deploy_secrets.go
@@ -0,0 +1,128 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package cli
+
+import (
+	"context"
+	"errors"
+	"sort"
+	"strings"
+
+	awssecretsmanager "github.com/aws/copilot-cli/internal/pkg/aws/secretsmanager"
+	awsssm "github.com/aws/copilot-cli/internal/pkg/aws/ssm"
+	"github.com/aws/copilot-cli/internal/pkg/manifest"
+	"github.com/aws/copilot-cli/internal/pkg/term/color"
+	"github.com/aws/copilot-cli/internal/pkg/term/log"
+)
+
+const (
+	secretStoreSSM            = "SSM Parameter Store"
+	secretStoreSecretsManager = "Secrets Manager"
+)
+
+type missingSecret struct {
+	name  string
+	store string
+}
+
+func (o *deploySvcOpts) warnMissingSecrets(ctx context.Context, mft any) {
+	for _, secret := range o.missingSecrets(ctx, mft) {
+		log.Warningf("%s secret %s does not exist; deployment may fail until it is created.\n",
+			secret.store, color.HighlightUserInput(secret.name))
+	}
+}
+
+func (o *deploySvcOpts) missingSecrets(ctx context.Context, mft any) []missingSecret {
+	var missing []missingSecret
+	seen := make(map[missingSecret]struct{})
+	for _, secret := range workloadSecrets(mft) {
+		name, store, ok := secretRef(secret)
+		if !ok {
+			continue
+		}
+		ref := missingSecret{name: name, store: store}
+		if _, ok := seen[ref]; ok {
+			continue
+		}
+		seen[ref] = struct{}{}
+		switch store {
+		case secretStoreSecretsManager:
+			if o.secretsmanager == nil {
+				continue
+			}
+			if _, err := o.secretsmanager.DescribeSecret(name); err != nil {
+				var notFound *awssecretsmanager.ErrSecretNotFound
+				if errors.As(err, &notFound) {
+					missing = append(missing, ref)
+				}
+			}
+		default:
+			if o.ssmParamGetter == nil {
+				continue
+			}
+			if _, err := o.ssmParamGetter.GetSecretValue(ctx, name); err != nil {
+				var notFound *awsssm.ErrParameterNotFound
+				if errors.As(err, &notFound) {
+					missing = append(missing, ref)
+				}
+			}
+		}
+	}
+	sort.Slice(missing, func(i, j int) bool {
+		if missing[i].store == missing[j].store {
+			return missing[i].name < missing[j].name
+		}
+		return missing[i].store < missing[j].store
+	})
+	return missing
+}
+
+func secretRef(secret manifest.Secret) (string, string, bool) {
+	if secret.RequiresImport() {
+		return "", "", false
+	}
+	name := secret.Value()
+	if name == "" {
+		return "", "", false
+	}
+	if secret.IsSecretsManagerName() || strings.Contains(name, ":secretsmanager:") {
+		return name, secretStoreSecretsManager, true
+	}
+	return name, secretStoreSSM, true
+}
+
+func workloadSecrets(mft any) []manifest.Secret {
+	switch mft := mft.(type) {
+	case *manifest.LoadBalancedWebService:
+		return ecsWorkloadSecrets(mft.TaskConfig, mft.Logging, mft.Sidecars)
+	case *manifest.BackendService:
+		return ecsWorkloadSecrets(mft.TaskConfig, mft.Logging, mft.Sidecars)
+	case *manifest.WorkerService:
+		return ecsWorkloadSecrets(mft.TaskConfig, mft.Logging, mft.Sidecars)
+	case *manifest.RequestDrivenWebService:
+		return appendSecrets(nil, mft.Secrets)
+	default:
+		return nil
+	}
+}
+
+func ecsWorkloadSecrets(task manifest.TaskConfig, logging manifest.Logging, sidecars map[string]*manifest.SidecarConfig) []manifest.Secret {
+	secrets := appendSecrets(nil, task.Secrets)
+	secrets = appendSecrets(secrets, logging.Secrets)
+	secrets = appendSecrets(secrets, logging.SecretOptions)
+	for _, sidecar := range sidecars {
+		if sidecar == nil {
+			continue
+		}
+		secrets = appendSecrets(secrets, sidecar.Secrets)
+	}
+	return secrets
+}
+
+func appendSecrets(dst []manifest.Secret, src map[string]manifest.Secret) []manifest.Secret {
+	for _, secret := range src {
+		dst = append(dst, secret)
+	}
+	return dst
+}
diff --git a/internal/pkg/cli/svc_deploy_secrets_test.go b/internal/pkg/cli/svc_deploy_secrets_test.go
new file mode 100644
index 00000000000..9e2709a2f35
--- /dev/null
+++ b/internal/pkg/cli/svc_deploy_secrets_test.go
@@ -0,0 +1,125 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package cli
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	awssecretsmanager "github.com/aws/copilot-cli/internal/pkg/aws/secretsmanager"
+	awsssm "github.com/aws/copilot-cli/internal/pkg/aws/ssm"
+	"github.com/aws/copilot-cli/internal/pkg/cli/mocks"
+	"github.com/aws/copilot-cli/internal/pkg/manifest"
+	"github.com/golang/mock/gomock"
+	"github.com/stretchr/testify/require"
+)
+
+func TestDeploySvcOpts_MissingSecrets(t *testing.T) {
+	testCases := map[string]struct {
+		inManifest string
+		setupMocks func(m *deploySvcSecretMocks)
+
+		wanted []missingSecret
+	}{
+		"returns SSM and Secrets Manager refs that do not exist": {
+			inManifest: `
+name: frontend
+type: "Load Balanced Web Service"
+image:
+  location: nginx
+  port: 80
+secrets:
+  DB_PASSWORD: /copilot/phonetool/test/secrets/db-password
+logging:
+  secretOptions:
+    LOG_TOKEN: /copilot/phonetool/test/secrets/log-token
+sidecars:
+  xray:
+    image: xray-daemon
+    secrets:
+      API_TOKEN:
+        secretsmanager: sidecar-secret
+`,
+			setupMocks: func(m *deploySvcSecretMocks) {
+				m.ssm.EXPECT().GetSecretValue(gomock.Any(), "/copilot/phonetool/test/secrets/db-password").
+					Return("", &awsssm.ErrParameterNotFound{})
+				m.ssm.EXPECT().GetSecretValue(gomock.Any(), "/copilot/phonetool/test/secrets/log-token").
+					Return("log-token", nil)
+				m.secretsmanager.EXPECT().DescribeSecret("sidecar-secret").
+					Return(nil, &awssecretsmanager.ErrSecretNotFound{})
+			},
+			wanted: []missingSecret{
+				{name: "/copilot/phonetool/test/secrets/db-password", store: secretStoreSSM},
+				{name: "sidecar-secret", store: secretStoreSecretsManager},
+			},
+		},
+		"skips imported secrets and ignores validation errors that are not not-found errors": {
+			inManifest: `
+name: frontend
+type: "Backend Service"
+image:
+  location: nginx
+secrets:
+  IMPORTED:
+    from_cfn: stack-SecretName
+  API_KEY: /copilot/phonetool/test/secrets/api-key
+`,
+			setupMocks: func(m *deploySvcSecretMocks) {
+				m.ssm.EXPECT().GetSecretValue(gomock.Any(), "/copilot/phonetool/test/secrets/api-key").
+					Return("", errors.New("access denied"))
+			},
+		},
+		"deduplicates repeated refs": {
+			inManifest: `
+name: frontend
+type: "Request-Driven Web Service"
+image:
+  location: nginx
+secrets:
+  FIRST: shared-secret
+  SECOND: shared-secret
+`,
+			setupMocks: func(m *deploySvcSecretMocks) {
+				m.ssm.EXPECT().GetSecretValue(gomock.Any(), "shared-secret").
+					Return("", &awsssm.ErrParameterNotFound{})
+			},
+			wanted: []missingSecret{
+				{name: "shared-secret", store: secretStoreSSM},
+			},
+		},
+	}
+
+	for name, tc := range testCases {
+		t.Run(name, func(t *testing.T) {
+			ctrl := gomock.NewController(t)
+			defer ctrl.Finish()
+
+			mockClients := deploySvcSecretMocks{
+				ssm:            mocks.NewMocksecretGetter(ctrl),
+				secretsmanager: mocks.NewMocksecretDeleter(ctrl),
+			}
+			tc.setupMocks(&mockClients)
+
+			opts := deploySvcOpts{
+				ssmParamGetter: mockClients.ssm,
+				secretsmanager: mockClients.secretsmanager,
+			}
+			require.ElementsMatch(t, tc.wanted, opts.missingSecrets(context.Background(), mustUnmarshalWorkload(t, tc.inManifest)))
+		})
+	}
+}
+
+type deploySvcSecretMocks struct {
+	ssm            *mocks.MocksecretGetter
+	secretsmanager *mocks.MocksecretDeleter
+}
+
+func mustUnmarshalWorkload(t *testing.T, raw string) any {
+	t.Helper()
+
+	mft, err := manifest.UnmarshalWorkload([]byte(raw))
+	require.NoError(t, err)
+	return mft.Manifest()
+}