diff --git a/.changelog/392.txt b/.changelog/392.txt
new file mode 100644
index 000000000..88e2e72bd
--- /dev/null
+++ b/.changelog/392.txt
@@ -0,0 +1,3 @@
+```release-note:enhancement
+diag: `ErrorsCount`, `WarningsCount`, `Errors` and `Warnings` functions have been added to `diag.Diagnostics`
+```
diff --git a/diag/diagnostics.go b/diag/diagnostics.go
index 1d42df718..b0e333326 100644
--- a/diag/diagnostics.go
+++ b/diag/diagnostics.go
@@ -70,3 +70,39 @@ func (diags Diagnostics) HasError() bool {
 
 	return false
 }
+
+// ErrorsCount returns the number of Diagnostic in Diagnostics that are SeverityError.
+func (diags Diagnostics) ErrorsCount() int {
+	return len(diags.Errors())
+}
+
+// WarningsCount returns the number of Diagnostic in Diagnostics that are SeverityWarning.
+func (diags Diagnostics) WarningsCount() int {
+	return len(diags.Warnings())
+}
+
+// Errors returns all the Diagnostic in Diagnostics that are SeverityError.
+func (diags Diagnostics) Errors() Diagnostics {
+	dd := Diagnostics{}
+
+	for _, d := range diags {
+		if SeverityError == d.Severity() {
+			dd = append(dd, d)
+		}
+	}
+
+	return dd
+}
+
+// Warnings returns all the Diagnostic in Diagnostics that are SeverityWarning.
+func (diags Diagnostics) Warnings() Diagnostics {
+	dd := Diagnostics{}
+
+	for _, d := range diags {
+		if SeverityWarning == d.Severity() {
+			dd = append(dd, d)
+		}
+	}
+
+	return dd
+}
diff --git a/diag/diagnostics_test.go b/diag/diagnostics_test.go
index 9b9ebb989..cdc58fcf5 100644
--- a/diag/diagnostics_test.go
+++ b/diag/diagnostics_test.go
@@ -4,6 +4,7 @@ import (
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
+
 	"github.com/hashicorp/terraform-plugin-framework/diag"
 	"github.com/hashicorp/terraform-plugin-framework/path"
 )
@@ -518,3 +519,179 @@ func TestDiagnosticsHasError(t *testing.T) {
 		})
 	}
 }
+
+func TestDiagnosticsErrorsCount(t *testing.T) {
+	t.Parallel()
+
+	type testCase struct {
+		diags    diag.Diagnostics
+		expected int
+	}
+	tests := map[string]testCase{
+		"nil": {
+			diags:    nil,
+			expected: 0,
+		},
+		"empty": {
+			diags:    diag.Diagnostics{},
+			expected: 0,
+		},
+		"errors": {
+			diags: diag.Diagnostics{
+				diag.NewErrorDiagnostic("Error Summary", "Error detail."),
+				diag.NewWarningDiagnostic("Warning Summary", "Warning detail."),
+			},
+			expected: 1,
+		},
+		"warnings": {
+			diags: diag.Diagnostics{
+				diag.NewWarningDiagnostic("Error Summary", "Error detail."),
+			},
+			expected: 0,
+		},
+	}
+
+	for name, test := range tests {
+		name, test := name, test
+		t.Run(name, func(t *testing.T) {
+			got := test.diags.ErrorsCount()
+
+			if diff := cmp.Diff(test.expected, got); diff != "" {
+				t.Fatalf("expected: %q, got: %q", test.expected, got)
+			}
+		})
+	}
+}
+
+func TestDiagnosticsWarningsCount(t *testing.T) {
+	t.Parallel()
+
+	type testCase struct {
+		diags    diag.Diagnostics
+		expected int
+	}
+	tests := map[string]testCase{
+		"nil": {
+			diags:    nil,
+			expected: 0,
+		},
+		"empty": {
+			diags:    diag.Diagnostics{},
+			expected: 0,
+		},
+		"errors": {
+			diags: diag.Diagnostics{
+				diag.NewErrorDiagnostic("Error Summary", "Error detail."),
+				diag.NewWarningDiagnostic("Warning Summary", "Warning detail."),
+			},
+			expected: 1,
+		},
+		"warnings": {
+			diags: diag.Diagnostics{
+				diag.NewErrorDiagnostic("Error Summary", "Error detail."),
+			},
+			expected: 0,
+		},
+	}
+
+	for name, test := range tests {
+		name, test := name, test
+		t.Run(name, func(t *testing.T) {
+			got := test.diags.WarningsCount()
+
+			if diff := cmp.Diff(test.expected, got); diff != "" {
+				t.Fatalf("expected: %q, got: %q", test.expected, got)
+			}
+		})
+	}
+}
+
+func TestDiagnosticsErrors(t *testing.T) {
+	t.Parallel()
+
+	type testCase struct {
+		diags    diag.Diagnostics
+		expected diag.Diagnostics
+	}
+	tests := map[string]testCase{
+		"nil": {
+			diags:    nil,
+			expected: diag.Diagnostics{},
+		},
+		"empty": {
+			diags:    diag.Diagnostics{},
+			expected: diag.Diagnostics{},
+		},
+		"errors": {
+			diags: diag.Diagnostics{
+				diag.NewErrorDiagnostic("Error Summary", "Error detail."),
+				diag.NewWarningDiagnostic("Warning Summary", "Warning detail."),
+			},
+			expected: diag.Diagnostics{
+				diag.NewErrorDiagnostic("Error Summary", "Error detail."),
+			},
+		},
+		"warnings": {
+			diags: diag.Diagnostics{
+				diag.NewWarningDiagnostic("Warning Summary", "Warning detail."),
+			},
+			expected: diag.Diagnostics{},
+		},
+	}
+
+	for name, test := range tests {
+		name, test := name, test
+		t.Run(name, func(t *testing.T) {
+			got := test.diags.Errors()
+
+			if diff := cmp.Diff(test.expected, got); diff != "" {
+				t.Fatalf("expected: %q, got: %q", test.expected, got)
+			}
+		})
+	}
+}
+
+func TestDiagnosticsWarnings(t *testing.T) {
+	t.Parallel()
+
+	type testCase struct {
+		diags    diag.Diagnostics
+		expected diag.Diagnostics
+	}
+	tests := map[string]testCase{
+		"nil": {
+			diags:    nil,
+			expected: diag.Diagnostics{},
+		},
+		"empty": {
+			diags:    diag.Diagnostics{},
+			expected: diag.Diagnostics{},
+		},
+		"errors": {
+			diags: diag.Diagnostics{
+				diag.NewErrorDiagnostic("Error Summary", "Error detail."),
+			},
+			expected: diag.Diagnostics{},
+		},
+		"warnings": {
+			diags: diag.Diagnostics{
+				diag.NewErrorDiagnostic("Error Summary", "Error detail."),
+				diag.NewWarningDiagnostic("Warning Summary", "Warning detail."),
+			},
+			expected: diag.Diagnostics{
+				diag.NewWarningDiagnostic("Warning Summary", "Warning detail."),
+			},
+		},
+	}
+
+	for name, test := range tests {
+		name, test := name, test
+		t.Run(name, func(t *testing.T) {
+			got := test.diags.Warnings()
+
+			if diff := cmp.Diff(test.expected, got); diff != "" {
+				t.Fatalf("expected: %q, got: %q", test.expected, got)
+			}
+		})
+	}
+}