Employment Act (Chapter 91): Primary legislation governing employment relationships in Singapore. While LOI isn't a formal contract, it should align with basic employment principles as it may lead to employment.

Personal Data Protection Act (PDPA): Legislation governing the collection, use, and disclosure of personal data. Relevant for handling personal information in the LOI and ensuring proper consent and disclosure.

Anti-Discrimination Guidelines: Including Tripartite Guidelines on Fair Employment Practices (TGFEP) and Fair Consideration Framework. Ensures the LOI doesn't contain discriminatory elements.

Misrepresentation Act (Chapter 390): Ensures all statements made in the LOI are truthful and accurate, avoiding any false or misleading representations.

Singapore Contract Law: Basic contract law principles that govern the formation of legal documents, ensuring clear expression of intent without creating unintended legal obligations.

Industry-Specific Regulations: Any specific regulations that apply to the particular industry or sector where the job application is being made.

Professional Body Requirements: Requirements set by professional bodies or associations relevant to the position being applied for.

Immigration Laws: Relevant if applying as a foreign worker, ensuring compliance with Singapore's immigration and work permit requirements.