Mirror image rule

Contract law

Formation
Capacity Offer and acceptance Meeting of the minds² Abstraction principle^4,5 Posting rule¹ Mirror image rule Invitation to treat Firm offer Consideration^1,4 Implication-in-fact Collateral contract
Defences
Misrepresentation Mistake Threats and unequal bargaining power Illegality and public policy Unconscionability Culpa in contrahendo² Force majeure Frustration of purpose Impossibility Impracticability Hardship Set-off Illusory promise¹ Statute of frauds¹ Non est factum¹ Unclean hands¹ Accord and satisfaction¹ Exculpatory clause
Interpretation
Parol evidence³ Contract of adhesion Integration clause Contra proferentem UNIDROIT Principles
Dispute resolution
Choice of law clause Forum selection clause Hague Choice of Court Convention Arbitration New York Convention UNCITRAL Model Law Mediation Singapore Mediation Convention Enforcement of foreign judgments Hague Judgments Convention
Rights of third parties
Privity of contract¹ Assignment Delegation Novation Third-party beneficiary
Breach of contract
Anticipatory repudiation Cover Exclusion clause Efficient breach Deviation Fundamental breach
Remedies
Specific performance³ Money damages Liquidated, stipulated, or penal damages³ Rescission
Quasi-contractual obligations
Promissory estoppel¹ Quantum meruit¹ Unjust enrichment Restitution Negotiorum gestio²
Duties of parties
Duty of honest contractual performance (or doctrine of abuse of rights)⁶ Duty of good faith (also implied covenant of good faith and fair dealing or duty to negotiate in good faith)⁷ Contract A and Contract B in Canadian contract law⁶
Related areas of law
Conflict of laws Commercial law
By jurisdiction
Australia Canada China (mainland) India Saudi Arabia United Kingdom England and Wales Scotland United States
Other law areas
Tort law Property law Wills, trusts, and estates Criminal law Evidence
Notes
1 Specific to common law jurisdictions 2 Specific to civil and mixed law jurisdictions 3 Historically restricted in common law jurisdictions but generally accepted elsewhere; availability varies between contemporary common law jurisdictions 4 Specific to the German Bürgerliches Gesetzbuch and other civil codes based on the pandectist tradition 5 Explicitly rejected by the UNIDROIT Principles of International Commercial Contracts 6 Specific to Canadian contract law both in Québec and in the country's common law provinces 7 Specific to civil law jurisdictions, the American Uniform Commercial Code, and Canadian jurisprudence in both Québec and the common law provinces pertaining to contractual and pre-contractual negotiation

In the law of contracts, the mirror image rule, also referred to as an unequivocal and absolute acceptance requirement, states that an offer must be accepted exactly with no modifications. The offeror is the master of his own offer. An attempt to accept the offer on different terms instead creates a counter-offer, and this constitutes a rejection of the original offer.