How to fix Error: Failed to read variables from terraform.tfvars in Terraform

Ensure the file is named exactly terraform.tfvars (not terraform.tfvar or terraform.tfvars.json unless you're specifically using JSON format).

# List files in current directory
ls -la terraform.tfvars

# Or from parent directory
ls -la your-project/terraform.tfvars

The file must be in the root module directory where you run terraform commands. If it's in a subdirectory, you'll need to use the -var-file flag.

Check for HCL syntax errors in terraform.tfvars. Common mistakes include:
- Missing quotes around string values: instance_type = t2.micro should be instance_type = "t2.micro"
- Incorrect object/map syntax: tags = { Name = "test" } (must use =)
- Missing commas between properties (not required in HCL but object syntax must be correct)

# Correct syntax examples
region           = "us-east-1"
instance_count   = 3
enable_feature   = true
tags             = { Name = "web-server", Env = "prod" }
availability_zones = ["us-east-1a", "us-east-1b"]

Review your file character by character for these issues.

Every variable used in terraform.tfvars must be declared in a .tf file (typically variables.tf). Variable declarations define what variables Terraform expects.

# variables.tf
variable "region" {
  type        = string
  description = "AWS region"
  default     = "us-east-1"
}

variable "instance_count" {
  type    = number
  default = 1
}

variable "tags" {
  type = map(string)
}

If terraform.tfvars contains a variable that doesn't have a corresponding declaration, Terraform will fail. Add the missing declarations.

Terraform must be run from the directory containing your root module .tf files. If terraform.tfvars is in a different location, use the -var-file flag.

# If terraform.tfvars is in current directory (default behavior)
terraform plan

# If terraform.tfvars is elsewhere
terraform plan -var-file="./environments/prod.tfvars"

# Multiple .tfvars files
terraform plan -var-file="./common.tfvars" -var-file="./prod.tfvars"

The auto-loading of terraform.tfvars only works when the file is in the same directory as your .tf files.

terraform validate will often provide more specific error details about what's wrong with your configuration and .tfvars files.

terraform validate

This command checks syntax without making any cloud API calls, so it's safe to run repeatedly. It will tell you exactly which line or variable is causing the problem.