A pairing-free certificateless trusted access protocol for WLAN is proposed based on the certificateless public key cryptography and the trusted computing technologies. This protocol does not require the use of certificates and yet does not have the inherent key escrow feature of identity-based public key cryptography (ID-PKC). Taking the efficiency of this protocol into consideration, the following strategies are adopted in our protocol design. The platform authentication and integrity verification of station (STA) to authentication server (AS) are achieved during the authentication procedure. In addition, the explicit key agreement between STA and access point (AP) is adopted without 4-way handshake. Therefore, the mutual authentication and unicast session key agreement between STA and AP as well as the platform trusted verification are realized within 3 protocol rounds. In particular, the point multiplication on the elliptic curve is used instead of bilinear which causes significant computation overhead in the traditional certificateless public key cryptography. The security properties of the new protocol are examined using a very strong security model—the extended Canetti-Krawczyk (eCK) model, and the results show that the protocol is secure on the assumption that the Gap Diffie-Hellman problem is a difficult problem. The analytic comparisons show that the new protocol is very efficient in both computing and communication costs.