Canada Labour Code

Basic Freedoms

(i) Every employee is free to join the trade union of his/her choice and to participate in its lawful activities.
Prohibitions Relating to Employers
(i) No employer or person acting on behalf of an employer shall:
(a) refuse to employ or to continue to employ or suspend, transfer, lay off or otherwise discriminate against any person with respect to employment, pay or any other term or condition of employment or intimidate, threaten or otherwise discipline any person because the person...
(i) is or proposes to become, or seek to induce any other person to become, a member, officer or representative of a trade union or participate in the promotion, formation or administration of a trade union.