diff --git a/datadog/fwprovider/observability_pipeline/processor_validator.go b/datadog/fwprovider/observability_pipeline/processor_validator.go
new file mode 100644
index 0000000000..e83edaa20f
--- /dev/null
+++ b/datadog/fwprovider/observability_pipeline/processor_validator.go
@@ -0,0 +1,74 @@
+package observability_pipeline
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/hashicorp/terraform-plugin-framework/diag"
+	"github.com/hashicorp/terraform-plugin-framework/schema/validator"
+	"github.com/hashicorp/terraform-plugin-framework/types"
+)
+
+// coreProcessorFields are the common processor attributes that are NOT processor types.
+// Any other list attribute in the processor block is considered a processor type.
+var coreProcessorFields = map[string]struct{}{
+	"id":           {},
+	"enabled":      {},
+	"include":      {},
+	"display_name": {},
+}
+
+// ExactlyOneProcessorValidator validates that exactly one processor type block is specified
+type ExactlyOneProcessorValidator struct{}
+
+func (v ExactlyOneProcessorValidator) Description(ctx context.Context) string {
+	return "validates that exactly one processor type block is specified (e.g., filter, sample, quota)"
+}
+
+func (v ExactlyOneProcessorValidator) MarkdownDescription(ctx context.Context) string {
+	return v.Description(ctx)
+}
+
+func (v ExactlyOneProcessorValidator) ValidateObject(ctx context.Context, req validator.ObjectRequest, resp *validator.ObjectResponse) {
+	if req.ConfigValue.IsNull() || req.ConfigValue.IsUnknown() {
+		return
+	}
+
+	attrs := req.ConfigValue.Attributes()
+
+	var specifiedTypes []string
+	for attrName, attr := range attrs {
+		// Skip core processor fields
+		if _, isCoreField := coreProcessorFields[attrName]; isCoreField {
+			continue
+		}
+
+		if attr.IsNull() || attr.IsUnknown() {
+			continue
+		}
+
+		// Check if the list has any elements (processor type blocks are list nested blocks)
+		if list, ok := attr.(types.List); ok {
+			if len(list.Elements()) > 0 {
+				specifiedTypes = append(specifiedTypes, attrName)
+			}
+		}
+	}
+
+	if len(specifiedTypes) == 0 {
+		resp.Diagnostics.Append(diag.NewAttributeErrorDiagnostic(
+			req.Path,
+			"Missing Processor Type",
+			"A processor block must specify exactly one processor type (e.g., filter, sample, quota, parse_json, etc.).",
+		))
+		return
+	}
+
+	if len(specifiedTypes) > 1 {
+		resp.Diagnostics.Append(diag.NewAttributeErrorDiagnostic(
+			req.Path,
+			"Multiple Processor Types Specified",
+			fmt.Sprintf("A processor block must specify exactly one processor type, but found %d: %v. Each processor should only contain one type.", len(specifiedTypes), specifiedTypes),
+		))
+	}
+}
diff --git a/datadog/fwprovider/resource_datadog_observability_pipeline.go b/datadog/fwprovider/resource_datadog_observability_pipeline.go
index 12108d113d..68afc536f9 100644
--- a/datadog/fwprovider/resource_datadog_observability_pipeline.go
+++ b/datadog/fwprovider/resource_datadog_observability_pipeline.go
@@ -956,6 +956,9 @@ func (r *observabilityPipelineResource) Schema(_ context.Context, _ resource.Sch
 									"processor": schema.ListNestedBlock{
 										Description: "The processor contained in this group.",
 										NestedObject: schema.NestedBlockObject{
+											Validators: []validator.Object{
+												observability_pipeline.ExactlyOneProcessorValidator{},
+											},
 											Attributes: map[string]schema.Attribute{
 												"id": schema.StringAttribute{
 													Required:    true,