Exhibit 5.1

150 Third Avenue South, Suite 2800

Nashville, TN 37201

(615) 742-6200

May 28, 2015

HealthStream, Inc.

209 10^th Avenue South, Suite 450

Nashville, Tennessee 37203

Ladies and Gentlemen:

We have acted as counsel for HealthStream, Inc., a Tennessee corporation (the “Company”), in connection with the offering of shares of common stock, no par value per share (“Common Stock”), by the Company pursuant to the Underwriting Agreement, dated May 21, 2015 (the “Underwriting Agreement”), among the Company, and William Blair & Company, L.L.C. and Raymond James & Associates, Inc., as the representatives of the several underwriters named in Schedule A thereto (the “Underwriters”). The Underwriting Agreement provides for the purchase by the Underwriters of 3,869,750 shares of the Company’s Common Stock, consisting of 3,365,000 shares of Common Stock to be sold by the Company (the “Firm Shares”) and, at the option of the Underwriters, up to 504,750 additional shares of Common Stock pursuant to an overallotment option (the “Option Shares” and, collectively with the Firm Shares, the “Shares”). The Shares are to be offered and sold by the Company pursuant to a prospectus supplement, dated May 21, 2015 (the “Prospectus Supplement”) and the accompanying base prospectus dated August 22, 2014 (the “Base Prospectus” and collectively with the Prospectus Supplement, the “Prospectus”) that form part of the Company’s registration statement on Form S-3, as amended (File No. 333-198059) (the “Registration Statement”), filed by the Company with the Securities and Exchange Commission under the Securities Act of 1933, as amended.

In rendering our opinion, we have reviewed the Prospectus Supplement, the Registration Statement and the exhibits thereto. We have also reviewed such corporate documents and records of the Company, such certificates of public officials and such other matters as we have deemed necessary or appropriate for purposes of this opinion. We also have been furnished with, and with your consent have relied upon, certificates of officers of the Company with respect to certain factual matters.

We have assumed the authenticity of all documents submitted to us as originals, the genuineness of all signatures, the conformity to authentic original documents of all documents submitted to us as certified, conformed or photostatic copies and the legal capacities of all natural persons.

The opinions expressed below are limited to the State of Tennessee and the federal laws of the United States of America. Without limiting the generality of the foregoing, we express no opinion with respect to (i) state securities or “Blue Sky” laws or (ii) state or federal antitrust laws.

HealthStream, Inc.

May 28, 2015

Page 2

Based upon the foregoing, and subject to the assumptions, qualifications and limitations set forth herein, we are of the opinion that, when issued and delivered against payment therefore in accordance with the terms of the Underwriting Agreement, the Shares will be duly authorized and validly issued, fully paid and nonassessable.

Our opinion is rendered as of the date hereof, and we assume no obligation to advise you of changes in law or fact (or the effect thereof on the opinions expressed herein) that hereafter may come to our attention.

We hereby consent to the filing of this opinion as an Exhibit to a current report on Form 8-K, which is incorporated by reference into the Registration Statement, and to the reference to us under the caption “Legal Matters” in the Prospectus Supplement dated May 28, 2015. In giving such consent, we do not thereby admit that we are an “expert” within the meaning of the Securities Act.

Very truly yours,

/s/ Bass, Berry & Sims PLC

14288405.1