- Cafeteria Plan
- Calendar Year
- Call
- Callable
- Capital Asset
- Capital Expenditure
- Capital Gain
- Capital Gain Distributions
- Capital Improvement
- Capital Loss
- Capital Stock
- Capitalize
- Carryback/Carryover
- Cash Equivalent Doctrine
- Cash Method of Accounting
- Cash value in a life insurance policy
- Casualty
- Casualty Loss
- Certificate
- Certified Historic Structure
- Change in Accounting Method
- Change in Accounting Period
- Charitable Contributions
- Child
- Child and Dependent Care Credit
- Child Support Payments
- Child Tax Credit
- Claim of Right
- Class Life Asset Depreciation Range (CLADR)
- Cleared Funds
- Closed Year
- Collection Due Process
- Commission
- Commodity Futures
- Common Stock
- Common-Law State
- Community Income
- Community Property
- Commuting
- Compensation
- Condemnation
- Condemnation Award
- Constructive Receipt
- Contract Price
- Convention Expenses
- Convertible
- Copyright
- Corporation
- Cost
- Cost Depletion
- Cost Method of Inventory Valuation
- Cost of Goods Sold
- Cost of Maintaining a Home
- Cost or Market, Whichever Is Lower
- Cost Recovery
- Coupon Bond
- Coverdell Education Savings Account (ESA)
- Custodial Parent